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1. Shard Calculation

Query:

Response:

Calculated Shard: 152 (from laksa147)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa152.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://en.wikipedia.org/wiki/Human_body_temperature\')), getAhrefsUnparsedNoserviceFromURL(\'https://en.wikipedia.org/wiki/Human_body_temperature\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature","crawl_time":1775958218,"first_indexed_time":1408596675,"http_code":200,"src_unparsed":"org,wikipedia!en,\/wiki\/Human_body_temperature s443","src_root_hash":"17790707453426894952","history_drop_reason":null,"meta_title":"Human body temperature - Wikipedia","meta_descriptions":[],"attrs_boilerpipe_text":"Normal human body temperature\n(\nnormothermia\n,\neuthermia\n) is the typical\ntemperature\nrange found in\nhumans\n. The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F).\n[\n8\n]\n[\n9\n]\nHuman body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the\nbody\nthe measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a\nhomeostatic\nfunction known as\nthermoregulation\n, in which adjustment of temperature is triggered by the\ncentral nervous system\n.\nMethods of measurement\n[\nedit\n]\nA\nmedical thermometer\nshowing a temperature reading of 38.7 °C (101.7 °F)\nTaking a human's temperature is an initial part of a full\nclinical examination\n. There are various types of\nmedical thermometers\n, as well as sites used for measurement, including:\nUnder the armpit (axillary temperature)\nIn the mouth (oral temperature)\nIn the\nrectum\n(rectal temperature)\nIn the ear (tympanic temperature)\nOn the skin of the forehead over the\ntemporal artery\nUsing\nheat flux sensors\nDiurnal variation in body temperature, ranging from about 37.5 °C (99.5 °F) from 10 a.m. to 6 p.m., and falling to about 36.4 °C (97.5 °F) from 2 a.m. to 6 a.m. (Based on figure in entry for 'Animal Heat' in 11th edition of the\nEncyclopædia Britannica\n, 1910)\nTemperature control\n(\nthermoregulation\n) is a\nhomeostatic\nmechanism that keeps the organism at optimum\noperating temperature\n, as the temperature affects the rate of\nchemical reactions\n. In\nhumans\n, the average internal temperature is widely accepted to be 37 °C (98.6 °F), a \"normal\" temperature established in the 1800s.  But newer studies show that average internal temperature for men and women is 36.4 °C (97.5 °F).\n[\n10\n]\nNo person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's\ncircadian rhythm\n. The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors.\n[\n11\n]\nIn addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.90 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day.\nNormal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures.  The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F).\n[\n12\n]\nThis means that any oral temperature between 36.3 and 37.3 °C (97.3 and 99.1 °F) is likely to be normal.\n[\n13\n]\nThe normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F).\n[\n8\n]\n[\n9\n]\nIn adults a review of the literature has found a wider range of 33.2–38.2 °C (91.8–100.8 °F) for normal temperatures, depending on the gender and location measured.\n[\n14\n]\nReported values vary depending on how it is measured: oral (under the tongue): 36.8 ± 0.4 °C (98.2 ± 0.7 °F),\n[\n15\n]\ninternal (\nrectal\n,\nvaginal\n): 37.0 °C (98.6 °F).\n[\n15\n]\nA rectal or vaginal measurement taken directly inside the body cavity is typically slightly higher than oral measurement, and oral measurement is somewhat higher than skin measurement. Other places, such as under the arm or in the ear, produce different typical temperatures.\n[\n15\n]\nWhile some people think of these averages as representing normal or ideal measurements, a wide range of temperatures has been found in healthy people.\n[\n5\n]\nThe body temperature of a healthy person varies during the day by about 0.5 °C (0.9 °F) with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change.\n[\n15\n]\nOther circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the\nnadir\n, is one of the primary markers for\ncircadian rhythms\n. The body temperature also changes when a person is hungry, sleepy, sick, or cold.\nBody temperature normally fluctuates over the day following\ncircadian rhythms\n, with the lowest levels around 4\n \na.m. and the highest in the late afternoon, between 4:00 and 6:00 p.m. (assuming the person sleeps at night and stays awake during the day).\n[\n12\n]\n[\n15\n]\nTherefore, an oral temperature of 37.3 °C (99.1 °F) would, strictly speaking, be a normal, healthy temperature in the afternoon but not in the early morning.\n[\n15\n]\nAn individual's body temperature typically changes by about 0.5 °C (0.9 °F) between its highest and lowest points each day.\n[\n15\n]\nBody temperature is sensitive to many hormones, so women have a temperature rhythm that varies with the\nmenstrual cycle\n, called a\ncircamensal\nrhythm.\n[\n11\n]\n[\nunreliable medical source?\n]\nA woman's\nbasal body temperature\nrises sharply after\novulation\n, as\nestrogen\nproduction decreases and\nprogesterone\nincreases.\nFertility awareness\nprograms use this change to identify when a woman has ovulated to achieve or avoid\npregnancy\n. During the\nluteal phase\nof the menstrual cycle, both the lowest and the average temperatures are slightly higher than during other parts of the cycle.  However, the amount that the temperature rises during each day is slightly lower than typical, so the highest temperature of the day is not very much higher than usual.\n[\n16\n]\n[\nunreliable medical source?\n]\nHormonal contraceptives\nboth suppress the circamensal rhythm and raise the typical body temperature by about 0.6 °C (1.1 °F).\n[\n11\n]\n[\nunreliable medical source?\n]\nTemperature also may vary with the change of\nseasons\nduring each year.  This pattern is called a\ncircannual\nrhythm.\n[\n16\n]\n[\nunreliable medical source?\n]\nStudies of seasonal variations have produced inconsistent results.  People living in different climates may have different seasonal patterns.\n[\ncitation needed\n]\nIt has been found that physically active individuals have larger changes in body temperature throughout the day. Physically active people have been reported to have lower body temperatures than their less active peers in the early morning and similar or higher body temperatures later in the day.\n[\n17\n]\nWith increased age, both average body temperature and the amount of daily variability in the body temperature tend to decrease.\n[\n16\n]\n[\nunreliable medical source?\n]\nElderly people may have a decreased ability to generate body heat during a fever, so even a\nsomewhat elevated temperature\ncan indicate a serious underlying cause in\ngeriatrics\n. One study suggested that the average body temperature has also decreased since the 1850s.\n[\n18\n]\nThe study's authors believe the most likely explanation for the change is a reduction in inflammation at the population level due to decreased chronic infections and improved hygiene.\n[\n19\n]\nMeasurement methods\n[\nedit\n]\nTemperature by measurement technique\n[\n14\n]\nMethod\nWomen\nMen\nOral\n33.2–38.1 °C (91.8–100.6 °F)\n35.7–37.7 °C (96.3–99.9 °F)\nRectal\n36.8–37.1 °C (98.2–98.8 °F)\n36.7–37.5 °C (98.1–99.5 °F)\nTympanic\n35.7–37.5 °C (96.3–99.5 °F)\n35.5–37.5 °C (95.9–99.5 °F)\nAxillary\n35.5–37.0 °C (95.9–98.6 °F)\nDifferent methods used for measuring temperature produce different results.  The temperature reading depends on which part of the body is being measured.  The typical daytime temperatures among healthy adults are as follows:\nTemperature in the rectum (rectal), vagina, or in the ear (tympanic) is about 37.5 °C (99.5 °F)\n[\n20\n]\n[\nmedical citation needed\n]\nTemperature in the mouth (oral) is about 36.8 °C (98.2 °F)\n[\n12\n]\nTemperature under the arm (axillary) is about 36.5 °C (97.7 °F)\n[\n20\n]\n[\nmedical citation needed\n]\nGenerally, oral, rectal, gut, and core body temperatures, although slightly different, are well-correlated.\n[\ncitation needed\n]\nOral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open.\nMouth breathing\n, cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures.\n[\n21\n]\nEach measurement method also has different normal ranges depending on sex.\n[\n14\n]\nInfrared thermometer\n[\nedit\n]\nAs of 2016, reviews of infrared thermometers have found them to be of variable accuracy.\n[\n22\n]\nThis includes tympanic infrared thermometers in children.\n[\n23\n]\nVariations due to outside factors\n[\nedit\n]\nSleep disturbances also affect temperatures.  Normally, body temperature drops significantly at a person's normal bedtime and throughout the night.  Short-term\nsleep deprivation\nproduces a higher temperature at night than normal, but long-term sleep deprivation appears to reduce temperatures.\n[\n24\n]\nInsomnia\nand poor sleep quality are associated with smaller and later drops in body temperature.\n[\n25\n]\nSimilarly, waking up unusually early, sleeping in,\njet lag\nand changes to\nshift work\nschedules may affect body temperature.\nA temperature\nsetpoint\nis the level at which the body attempts to maintain its temperature.  When the setpoint is raised, the result is a fever.  Most fevers are caused by\ninfectious disease\nand can be lowered, if desired, with\nantipyretic\nmedications.\nAn early morning temperature higher than 37.3 °C (99.1 °F) or a late afternoon temperature higher than 37.7 °C (99.9 °F) is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint.\n[\n15\n]\nLower thresholds are sometimes appropriate for elderly people.\n[\n15\n]\nThe normal daily temperature variation is typically 0.5 °C (0.90 °F), but can be greater among people recovering from a fever.\n[\n15\n]\nAn organism at optimum temperature is considered\nafebrile\n, meaning \"\nwithout fever\n\".\n[\n26\n]\nIf temperature is raised, but the setpoint is not raised, then the result is\nhyperthermia\n.\nHyperthermia occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably.  Hyperthermia at or above about 40 °C (104 °F) is a life-threatening medical emergency that requires immediate treatment.  Common symptoms include headache, confusion, and fatigue.  If sweating has resulted in dehydration, then the affected person may have dry, red skin.\nIn a medical setting, mild hyperthermia is commonly called\nheat exhaustion\nor\nheat prostration\n; severe hyperthermia is called\nheat stroke\n.  Heatstroke may come on suddenly, but it usually follows the untreated milder stages.  Treatment involves cooling and rehydrating the body; fever-reducing drugs are useless for this condition.  This may be done by moving out of direct sunlight to a cooler and shaded environment, drinking water, removing clothing that might keep heat close to the body, or sitting in front of a fan. Bathing in tepid or cool water, or even just\nwashing the face\nand other exposed areas of the skin, can be helpful.\nWith fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers.\nIn hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be\ndeliberately induced as a medical treatment\n. Symptoms usually appear when the body's core temperature drops by 1–2 °C (1.8–3.6 °F) below normal temperature.\nBasal body temperature\n[\nedit\n]\nBasal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature.  In women, temperature differs at various points in the\nmenstrual cycle\n, and this can be used in the long term to track ovulation both to aid conception or avoid pregnancy.  This process is called\nfertility awareness\n.\nCore temperature, also called core body temperature, is the operating temperature of an\norganism\n, specifically in deep structures of the body such as the\nliver\n, in comparison to temperatures of peripheral tissues.  Core temperature is normally maintained within a narrow range so that essential enzymatic reactions can occur. Significant core temperature elevation (\nhyperthermia\n) or depression (\nhypothermia\n) over more than a brief period of time is fatal.\nTemperature examination in the\nheart\n, using a catheter, is the traditional\ngold standard\nmeasurement used to estimate core temperature (oral temperature is affected by hot or cold drinks, ambient temperature fluctuations as well as mouth-breathing). Since catheters are highly invasive, the generally accepted alternative for measuring core body temperature is through rectal measurements. Rectal temperature is expected to be approximately 1 °F (0.56 °C) higher than an oral temperature taken on the same person at the same time. Ear thermometers measure temperature from the\ntympanic membrane\nusing\ninfrared\nsensors and also aim to measure core body temperature, since the blood supply of this membrane is directly shared with the\nbrain\n. However, this method of measuring body temperature is not as accurate as rectal measurement and has a low sensitivity for fever, failing to determine three or four out of every ten fever measurements in children.\n[\n27\n]\nEar temperature measurement may be acceptable for observing trends in body temperature but is less useful in consistently identifying and diagnosing fever.\nUntil recently, direct measurement of core body temperature required either an ingestible device or surgical insertion of a probe. Therefore, a variety of indirect methods have commonly been used as the preferred alternative to these more accurate albeit more invasive methods.  The\nrectal\nor\nvaginal\ntemperature is generally considered to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible\nthermistors\nin\ncapsule\nform were produced, allowing the temperature inside the\ndigestive tract\nto be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement.\n[\n28\n]\nMore recently, a new method using\nheat flux sensors\nhave been developed. Several research papers show that its accuracy is similar to the invasive methods.\n[\n29\n]\n[\n30\n]\n[\n31\n]\nMeasurement within the body finds internal variation temperatures as different as 21.5 °C (70.7 °F) for the\nradial artery\nand 31.1 °C (88.0 °F) for the\nbrachial artery\n.\n[\n32\n]\nIt has been observed that \"chaos\" has been \"introduced into physiology by the fictitious assumption of a constant blood temperature\".\n[\n32\n]\nTemperature variation\n[\nedit\n]\n44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F).\n[\n33\n]\n[\n34\n]\n43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur.\n42 °C (107.6 °F) – Subject may turn red. They may become comatose, be in severe delirium, and convulsions can occur.\n41 °C (105.8 °F) – (\nMedical emergency\n) – Fainting, severe headache, dizziness, confusion, hallucinations, delirium, and drowsiness can occur. There may also be\npalpitations\nand breathlessness.\n40 °C (104 °F) – Fainting, dehydration, weakness, headache, breathlessness, and dizziness may occur as well as profuse sweating.\n39 °C (102.2 °F) – Severe sweating, and red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer convulsions at this temperature.\n38 °C (100.4 °F) – (Classed as\nhyperthermia\nif not caused by a\nfever\n) – Feeling hot, sweating, feeling thirsty, feeling very uncomfortable.\n37.6 °C (99.7 °F) — Classed as a slight fever. May lose appetite, feeling hot, feeling uncomfortable, feeling thirsty.\n36.5–37.5 °C (97.7–99.5 °F) is a typically reported range for normal body temperature.\n[\n8\n]\n35.5 °C (95.9 °F) – Feeling cold, mild to moderate shivering. This can be a normal body temperature for sleeping.\n35 °C (95 °F) – Threshold for\nhypothermia\n. Intense shivering, numbness and bluish\/grayness of the skin. There is the possibility of heart irritability.\n34 °C (93.2 °F) – Severe shivering, loss of movement of fingers, blueness, and confusion. Some behavioral changes may take place.\n33 °C (91.4 °F) – Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heartbeat, shallow breathing. Shivering may stop. The subject may be unresponsive to certain stimuli.\n32 °C (89.6 °F) – (\nMedical emergency\n) – Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent. Reflex may be absent or very slight.\n31 °C (87.8 °F) – Comatose, very rarely conscious. No or slight reflexes.  Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems.\n28 °C (82.4 °F) – Severe heart rhythm disturbances are likely and breathing may stop at any time. The person may appear to be dead.\n[\ncitation needed\n]\n24–26 °C (75.2–78.8 °F) or less – Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures lower than 12.7 °C (54.9 °F).\n[\n35\n]\nThe lowest recorded core temperature from a patient with accidental hypothermia who survived without neurological\nsequelae\nis 11.8 °C (53.2 °F).\n[\n36\n]\nThere are non-verbal corporal cues that can hint at an individual experiencing a low body temperature, which can be used for those with\ndysphasia\nor infants.\n[\n37\n]\nExamples of non-\nverbal\ncues of\ncoldness\ninclude stillness and being lethargic, unusual paleness of skin among light-skinned people, and, among males, shrinkage, and contraction of the\nscrotum\n.\n[\n38\n]\nEffect of environment\n[\nedit\n]\nEnvironmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The\npsychrometric temperature\n, of which the\nwet-bulb temperature\nis the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value consistent with human life.\nA 2022 study on the effect of heat on young people found that the critical wet-bulb temperature at which heat stress can no longer be compensated, T\nwb,crit\n, in young, healthy adults performing tasks at modest metabolic rates mimicking basic activities of daily life was much lower than the 35 °C (95 °F) usually assumed, at about 30.55 °C (86.99 °F) in 36–40 °C (97–104 °F) humid environments, but progressively decreased in hotter, dry ambient environments.\n[\n39\n]\n[\n40\n]\nAt low temperatures the body thermoregulates by generating heat, but this becomes unsustainable at extremely low temperatures.\nHistorical understanding\n[\nedit\n]\nIn the 19th century, most books quoted \"blood heat\" as 98 °F, until a study published the mean (but not the variance) of a large sample as 36.88 °C (98.38 °F).\n[\n41\n]\nSubsequently, that mean was widely quoted as \"37 °C or 98.4 °F\"\n[\n42\n]\n[\n43\n]\nuntil editors realized 37 °C is equal to 98.6 °F, not 98.4 °F. The 37 °C value was set by German physician\nCarl Reinhold August Wunderlich\nin his 1868 book,\n[\n44\n]\nwhich put temperature charts into widespread clinical use.\n[\n45\n]\nDictionaries and other sources\n[\nwhich?\n]\nthat quoted these averages did add the word \"about\" to show that there is some variance, but generally did not state how wide the variance is.\n[\ncitation needed\n]\n^\nMarx J (2006).\nRosen's emergency medicine : concepts and clinical practice\n(6th ed.). Philadelphia: Mosby\/Elsevier. p. 2239.\nISBN\n \n978-0-323-02845-5\n.\nOCLC\n \n58533794\n.\n^\nHutchison JS, Ward RE, Lacroix J, Hébert PC, Barnes MA, Bohn DJ, et al. (June 2008). \"Hypothermia therapy after traumatic brain injury in children\".\nThe New England Journal of Medicine\n.\n358\n(23):\n2447–\n56.\ndoi\n:\n10.1056\/NEJMoa0706930\n.\nPMID\n \n18525042\n.\n^\nPryor JA, Prasad AS (2008).\nPhysiotherapy for Respiratory and Cardiac Problems: Adults and Paediatrics\n. Elsevier Health Sciences. p. 8.\nISBN\n \n978-0702039744\n.\nBody temperature is maintained within the range 36.5-37.5 °C. It is lowest in the early morning and highest in the afternoon.\n^\na\nb\nAxelrod YK, Diringer MN (May 2008). \"Temperature management in acute neurologic disorders\".\nNeurologic Clinics\n.\n26\n(2):\n585–\n603, xi.\ndoi\n:\n10.1016\/j.ncl.2008.02.005\n.\nPMID\n \n18514828\n.\n^\na\nb\nc\nLaupland KB (July 2009). \"Fever in the critically ill medical patient\".\nCritical Care Medicine\n.\n37\n(7 Suppl): S273-8.\ndoi\n:\n10.1097\/CCM.0b013e3181aa6117\n.\nPMID\n \n19535958\n.\n^\nGrunau BE, Wiens MO, Brubacher JR (September 2010). \"Dantrolene in the treatment of MDMA-related hyperpyrexia: a systematic review\".\nCjem\n.\n12\n(5):\n435–\n42.\ndoi\n:\n10.1017\/s1481803500012598\n.\nPMID\n \n20880437\n.\nDantrolene may also be associated with improved survival and reduced complications, especially in patients with extreme (≥ 42 °C) or severe (≥ 40 °C) hyperpyrexia\n^\nSharma HS, ed. (2007).\nNeurobiology of Hyperthermia\n(1st ed.). Elsevier. pp. \n175–\n177, 485.\nISBN\n \n9780080549996\n. Retrieved\n19 November\n2016\n.\nDespite the myriad of complications associated with heat illness, an elevation of core temperature above 41.0 °C (often referred to as fever or hyperpyrexia) is the most widely recognized symptom of this syndrome.\n^\na\nb\nc\nHutchison, James S.; et al. (June 2008).\n\"Hypothermia therapy after traumatic brain injury in children\"\n.\nNew England Journal of Medicine\n.\n358\n(23):\n2447–\n2456.\ndoi\n:\n10.1056\/NEJMoa0706930\n.\nPMID\n \n18525042\n.\nS2CID\n \n46833\n.\nWe hypothesized that, as compared with normothermia (36.5 to 37.5°C), treatment with hypothermia...\n^\na\nb\nLey, C; Heath, F; Hastie, T; Gao, Z; Protsiv, M; Parsonnet, J (5 September 2023).\n\"Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm\"\n.\nJAMA Internal Medicine\n.\n183\n(10):\n1128–\n1135.\ndoi\n:\n10.1001\/jamainternmed.2023.4291\n.\nPMC\n \n10481327\n.\nPMID\n \n37669046\n.\n^\nWeintraub, Karen (April 2020).\n\"Are Human Body Temperatures Cooling Down?\"\n.\nScientific American\n. Retrieved\n10 March\n2022\n.\n^\na\nb\nc\nKelly, Greg S. (March 2007).\n\"Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease\"\n(PDF)\n.\nAlternative Medicine Review\n.\n12\n(1):\n49–\n62.\nPMID\n \n17397267\n. Archived from\nthe original\n(PDF)\non 2017-08-09\n. Retrieved\n2016-12-28\n.\n^\na\nb\nc\nMackowiak, Philip A.; Wasserman, Steven S.; Levine, Myron M. (1992-09-23). \"A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich\".\nJournal of the American Medical Association\n.\n268\n(12):\n1578–\n1580.\ndoi\n:\n10.1001\/jama.1992.03490120092034\n.\nPMID\n \n1302471\n.\n^\nDel Bene, Victor E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.),\n\"Temperature\"\n,\nClinical Methods: The History, Physical, and Laboratory Examinations\n(3rd ed.), Boston: Butterworths,\nISBN\n \n978-0-409-90077-4\n,\nPMID\n \n21250173\n, retrieved\n2023-02-15\n{{\ncitation\n}}\n:  CS1 maint: work parameter with ISBN (\nlink\n)\n^\na\nb\nc\nSund-Levander, Märtha; Forsberg, Christina; Wahren, Lis Karen (2002). \"Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review\".\nScandinavian Journal of Caring Sciences\n.\n16\n(2):\n122–\n8.\ndoi\n:\n10.1046\/j.1471-6712.2002.00069.x\n.\nPMID\n \n12000664\n.\n^\na\nb\nc\nd\ne\nf\ng\nh\ni\nj\nLongo, Dan L., ed. (2011).\nHarrison's principles of internal medicine\n(18th ed.). New York: McGraw-Hill. p. 142.\nISBN\n \n978-0-07-174889-6\n. Archived from\nthe original\non 2012-04-29\n. Retrieved\n2012-03-16\n.\n^\na\nb\nc\nKelly, Greg S. (December 2006).\n\"Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging\"\n(PDF)\n.\nAlternative Medicine Review\n.\n11\n(4):\n278–\n93.\nPMID\n \n17176167\n. Archived from\nthe original\n(PDF)\non 2017-08-08\n. Retrieved\n2016-12-28\n.\n^\nAtkinson, G.; Coldwells, A.; Reilly, T.; Waterhouse, J. (January 1993). \"A comparison of circadian rhythms in work performance between physically active and inactive subjects\".\nErgonomics\n.\n36\n(\n1–\n3):\n273–\n281.\ndoi\n:\n10.1080\/00140139308967882\n.\nPMID\n \n8440222\n.\n^\nKatz, Brigit (16 January 2020).\n\"Human Body Temperature Is Getting Cooler, Study Finds\"\n.\nSmithsonian\n. Retrieved\n22 January\n2020\n.\n^\nProtsiv, Myroslava; Ley, Catherine; Lankester, Joanna; Hastie, Trevor;\nParsonnet, Julie\n(2020-01-07). Jit, Mark; Franco, Eduardo; Waalen, Jill; Rühli, Frank (eds.).\n\"Decreasing human body temperature in the United States since the Industrial Revolution\"\n.\neLife\n.\n9\ne49555.\ndoi\n:\n10.7554\/eLife.49555\n.\nISSN\n \n2050-084X\n.\nPMC\n \n6946399\n.\nPMID\n \n31908267\n.\n^\na\nb\nWong, Lena (1997). Elert, Glenn (ed.).\n\"Temperature of a healthy human (body temperature)\"\n.\nThe Physics Factbook\n. Retrieved\n2022-01-25\n.\n^\nNewman, B. H.; Martin, C. A. (October 2001).\n\"The effect of hot beverages, cold beverages, and chewing gum on oral temperature\"\n.\nTransfusion\n.\n41\n(10):\n1241–\n1243.\ndoi\n:\n10.1046\/j.1537-2995.2001.41101241.x\n.\nISSN\n \n0041-1132\n.\nPMID\n \n11606822\n.\nS2CID\n \n24681501\n.\n^\nKiekkas, P; Stefanopoulos, N; Bakalis, N; Kefaliakos, A; Karanikolas, M (April 2016). \"Agreement of infrared temporal artery thermometry with other thermometry methods in adults: systematic review\".\nJournal of Clinical Nursing\n.\n25\n(\n7–\n8):\n894–\n905.\ndoi\n:\n10.1111\/jocn.13117\n.\nPMID\n \n26994990\n.\n^\nZhen, C; Xia, Z; Long, L; Pu, Y (October 2014). \"Accuracy of infrared ear thermometry in children: a meta-analysis and systematic review\".\nClinical Pediatrics\n.\n53\n(12):\n1158–\n65.\ndoi\n:\n10.1177\/0009922814536774\n.\nPMID\n \n24879119\n.\nS2CID\n \n24982111\n.\n^\nPaprocki, Jonathan (2012-12-18).\n\"Sleep deprivation disrupts regulation of body heat\"\n.\nSleep Education\n. Retrieved\n2023-02-15\n.\n^\nLack, Leon C.; Gradisar, Michael; Van Someren, Eus J. W.; Wright, Helen R.; Lushington, Kurt (August 2008). \"The relationship between insomnia and body temperatures\".\nSleep Medicine Reviews\n.\n12\n(4):\n307–\n317.\ndoi\n:\n10.1016\/j.smrv.2008.02.003\n.\nISSN\n \n1087-0792\n.\nPMID\n \n18603220\n.\n^\n\"Define Afebrile\"\n.\n^\nDodd, Susanna R.; Lancaster, Gillian A.; Craig, Jean V.; Smyth, Rosalind L.; Williamson, Paula R. (April 2006). \"In a systematic review, infrared ear thermometry for fever diagnosis in children finds poor sensitivity\".\nJournal of Clinical Epidemiology\n.\n59\n(4):\n354–\n7.\ndoi\n:\n10.1016\/j.jclinepi.2005.10.004\n.\nPMID\n \n16549256\n.\n^\nMcKenzie, Jack E.; Osgood, David W. (2004). \"Validation of a new telemetric core temperature monitor\".\nJournal of Thermal Biology\n.\n29\n(\n7–\n8): 605.\nBibcode\n:\n2004JTBio..29..605M\n.\ndoi\n:\n10.1016\/j.jtherbio.2004.08.020\n.\n^\nNidermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel (January 2014).\n\"Prediction of Human Core Body Temperature Using Non-Invasive Measurement Methods\"\n.\nInternational Journal of Biometeorology\n.\n58\n(1):\n7–\n15.\nBibcode\n:\n2014IJBm...58....7N\n.\ndoi\n:\n10.1007\/s00484-013-0687-2\n.\nhdl\n:\n20.500.11850\/80468\n.\nPMID\n \n23760405\n.\nS2CID\n \n11772946\n.\n^\nMendt, Stefan; Maggioni, Martina Ana; Nordine, Michael; Steinach, Mathias; Opatz, Oliver; Belavy, Daniel; Felsenberg, Dieter; Koch, Joachim; Shang, Peng; Hanns-Christian, Gunga; Stahn, Alexander (2017). \"Circadian Rhythms in Bed Rest: Monitoring Core Body Temperature via Heat-Flux Approach Is Superior to Skin Surface Temperature\".\nChronobiology International\n.\n34\n(5):\n666–\n676.\ndoi\n:\n10.1080\/07420528.2016.1224241\n.\nPMID\n \n27726448\n.\nS2CID\n \n205581198\n.\n^\nUth, Marc-Florian; Koch, Jochim; Sattler, Frank (2016).\n\"Body Core Temperature Sensing: Challenges and New Sensor Technologies\"\n.\nProcedia Engineering\n.\n168\n:\n89–\n92.\ndoi\n:\n10.1016\/j.proeng.2016.11.154\n.\n^\na\nb\nBazett, H. C.; Love, L.; Newton, M.; Eisenberg, L.; Day, R.; Forster, R. (1948). \"Temperature Changes in Blood Flowing in Arteries and Veins in Man\".\nJournal of Applied Physiology\n.\n1\n(1):\n3–\n19.\ndoi\n:\n10.1152\/jappl.1948.1.1.3\n.\nISSN\n \n8750-7587\n.\nPMID\n \n18887571\n.\n^\nChudler, Eric H.\n\"Biological Rhythms\"\n,\nNeuroscience for Kids\n, faculty.washington.edu\n^\ntemperature registered more than 115.7\"\n,\nBulletin Journal\n, August 7, 1980\n^\n\"2-latek z Polski rekordzistą. Przeżył wychłodzenie poniżej 12 st. C.\"\nDziennik Naukowy\n(in Polish). 5 December 2014\n. Retrieved\n23 September\n2022\n.\n^\nMroczek, T.; Gladki, M.; Skalski, J. (26 June 2020).\n\"Successful resuscitation from accidental hypothermia of 11.8°C: where is the lower bound for human beings?\"\n.\nEuropean Journal of Cardio-Thoracic Surgery\n.\n58\n(5):\n1091–\n1092.\ndoi\n:\n10.1093\/ejcts\/ezaa159\n.\nPMC\n \n7886275\n.\nPMID\n \n33084865\n.\n^\nTomita, K., et al. \"Examination of factors affecting the intraoral perception of object size: A preliminary study.\" Journal of oral rehabilitation 44.4 (2017): 237–243.\n^\nAl-Tubaikh, Jarrah Ali. \"Infectious Diseases and Tropical Medicine.\" Internal Medicine. Springer, Cham, 2017. 441–493.\n^\nVecellio, Daniel J.; Wolf, S. Tony; Cottle, Rachel M.; Kenney, W. Larry (2022-02-01).\n\"Evaluating the 35°C wet-bulb temperature adaptability threshold for young, healthy subjects (PSU HEAT Project)\"\n.\nJournal of Applied Physiology\n.\n132\n(2):\n340–\n345.\ndoi\n:\n10.1152\/japplphysiol.00738.2021\n.\nISSN\n \n8750-7587\n.\nPMC\n \n8799385\n.\nPMID\n \n34913738\n.\n^\nTimperley, Jocelyn (31 July 2022).\n\"Why you need to worry about the 'wet-bulb temperature'\n\"\n.\nThe Guardian\n.\n^\nInwit Publishing, Inc. and Inwit, LLC – Writings, Links and Software Demonstrations – A Fahrenheit–Celsius Activity\n, inwit.com\n^\nOxford Dictionary of English\n, 2010 edition, entry on \"blood heat\"\n^\nCollins English Dictionary\n, 1979 edition, entry on\n\"blood heat\"\n^\nWunderlich, Carl Reinhold August (1868).\nDas Verhalten der Eigenwärme in Krankheiten\n[\nThe behavior of the self-warmth in diseases\n]. Leipzig: O. Wigand.\n; its 1871 2nd edition translated into English and published with the title\nOn the temperature in diseases: a manual of medical thermometry\n.\n^\nFischetti, Mark (2018), \"Graphic Science: Goodbye, 98.6\",\nScientific American\n, vol. 319, no. 6 (December)","attrs_markdown":"[Jump to content](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#bodyContent)\n\nMain menu\n\nMain menu\n\nmove to sidebar\n\nhide\n\nNavigation\n\n- [Main page](https:\/\/en.wikipedia.org\/wiki\/Main_Page \"Visit the main page [z]\")\n- [Contents](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contents \"Guides to browsing Wikipedia\")\n- [Current events](https:\/\/en.wikipedia.org\/wiki\/Portal:Current_events \"Articles related to current events\")\n- [Random article](https:\/\/en.wikipedia.org\/wiki\/Special:Random \"Visit a randomly selected article [x]\")\n- [About Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:About \"Learn about Wikipedia and how it works\")\n- [Contact us](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contact_us \"How to contact Wikipedia\")\n\nContribute\n\n- [Help](https:\/\/en.wikipedia.org\/wiki\/Help:Contents \"Guidance on how to use and edit Wikipedia\")\n- [Learn to edit](https:\/\/en.wikipedia.org\/wiki\/Help:Introduction \"Learn how to edit Wikipedia\")\n- [Community portal](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Community_portal \"The hub for editors\")\n- [Recent changes](https:\/\/en.wikipedia.org\/wiki\/Special:RecentChanges \"A list of recent changes to Wikipedia [r]\")\n- [Upload file](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_upload_wizard \"Add images or other media for use on Wikipedia\")\n- [Special pages](https:\/\/en.wikipedia.org\/wiki\/Special:SpecialPages \"A list of all special pages [q]\")\n\n[![](https:\/\/en.wikipedia.org\/static\/images\/icons\/enwiki-25.svg) ![Wikipedia](https:\/\/en.wikipedia.org\/static\/images\/mobile\/copyright\/wikipedia-wordmark-en-25.svg) ![The Free Encyclopedia](https:\/\/en.wikipedia.org\/static\/images\/mobile\/copyright\/wikipedia-tagline-en-25.svg)](https:\/\/en.wikipedia.org\/wiki\/Main_Page)\n\n[Search](https:\/\/en.wikipedia.org\/wiki\/Special:Search \"Search Wikipedia [f]\")\n\nAppearance\n\n- [Donate](https:\/\/donate.wikimedia.org\/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en)\n- [Create account](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CreateAccount&returnto=Human+body+temperature \"You are encouraged to create an account and log in; however, it is not mandatory\")\n- [Log in](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UserLogin&returnto=Human+body+temperature \"You're encouraged to log in; however, it's not mandatory. [o]\")\n\nPersonal tools\n\n- [Donate](https:\/\/donate.wikimedia.org\/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en)\n- [Create account](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CreateAccount&returnto=Human+body+temperature \"You are encouraged to create an account and log in; however, it is not mandatory\")\n- [Log in](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UserLogin&returnto=Human+body+temperature \"You're encouraged to log in; however, it's not mandatory. [o]\")\n\n## Contents\nmove to sidebar\n\nhide\n\n- [(Top)](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature)\n- [1 Methods of measurement](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Methods_of_measurement)\n  Toggle Methods of measurement subsection\n  - [1\\.1 Variations](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Variations)\n  - [1\\.2 Natural rhythms](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Natural_rhythms)\n  - [1\\.3 Measurement methods](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Measurement_methods)\n  - [1\\.4 Infrared thermometer](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Infrared_thermometer)\n  - [1\\.5 Variations due to outside factors](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Variations_due_to_outside_factors)\n- [2 Concept](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Concept)\n  Toggle Concept subsection\n  - [2\\.1 Fever](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Fever)\n  - [2\\.2 Hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Hyperthermia)\n  - [2\\.3 Hypothermia](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Hypothermia)\n  - [2\\.4 Basal body temperature](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Basal_body_temperature)\n  - [2\\.5 Core temperature](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Core_temperature)\n  - [2\\.6 Internal variation](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Internal_variation)\n- [3 Temperature variation](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Temperature_variation)\n  Toggle Temperature variation subsection\n  - [3\\.1 Hot](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Hot)\n  - [3\\.2 Normal](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Normal)\n  - [3\\.3 Cold](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Cold)\n- [4 Effect of environment](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Effect_of_environment)\n- [5 Historical understanding](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#Historical_understanding)\n- [6 References](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#References)\n\nToggle the table of contents\n\n# Human body temperature\n16 languages\n\n- [العربية](https:\/\/ar.wikipedia.org\/wiki\/%D8%AD%D8%B1%D8%A7%D8%B1%D8%A9_%D8%A7%D9%84%D8%AC%D8%B3%D9%85_%D8%A7%D9%84%D8%A8%D8%B4%D8%B1%D9%8A \"حرارة الجسم البشري – Arabic\")\n- [تۆرکجه](https:\/\/azb.wikipedia.org\/wiki\/%D8%A7%DB%8C%D9%86%D8%B3%D8%A7%D9%86%DB%8C%D9%86_%D9%86%D9%88%D8%B1%D9%85%D8%A7%D9%84_%D8%A8%D8%AF%D9%86_%D8%A7%DB%8C%D8%B3%D8%AA%DB%8C%E2%80%8C%D9%84%DB%8C%DA%AF%DB%8C \"اینسانین نورمال بدن ایستی‌لیگی – South Azerbaijani\")\n- [Català](https:\/\/ca.wikipedia.org\/wiki\/Temperatura_corporal_humana \"Temperatura corporal humana – Catalan\")\n- [کوردی](https:\/\/ckb.wikipedia.org\/wiki\/%D9%BE%D9%84%DB%95%DB%8C_%DA%AF%DB%95%D8%B1%D9%85%DB%8C%DB%8C_%D9%84%DB%95%D8%B4%DB%8C_%D9%85%D8%B1%DB%86%DA%A4 \"پلەی گەرمیی لەشی مرۆڤ – Central Kurdish\")\n- [Español](https:\/\/es.wikipedia.org\/wiki\/Temperatura_del_cuerpo_humano \"Temperatura del cuerpo humano – Spanish\")\n- [فارسی](https:\/\/fa.wikipedia.org\/wiki\/%D8%AF%D9%85%D8%A7%DB%8C_%D8%A8%D8%AF%D9%86_%D8%A7%D9%86%D8%B3%D8%A7%D9%86 \"دمای بدن انسان – Persian\")\n- [Français](https:\/\/fr.wikipedia.org\/wiki\/Temp%C3%A9rature_corporelle_humaine \"Température corporelle humaine – French\")\n- [עברית](https:\/\/he.wikipedia.org\/wiki\/%D7%98%D7%9E%D7%A4%D7%A8%D7%98%D7%95%D7%A8%D7%AA_%D7%92%D7%95%D7%A3_%D7%A0%D7%95%D7%A8%D7%9E%D7%9C%D7%99%D7%AA \"טמפרטורת גוף נורמלית – Hebrew\")\n- [Հայերեն](https:\/\/hy.wikipedia.org\/wiki\/%D5%84%D5%A1%D6%80%D5%A4%D5%B8%D6%82_%D5%B4%D5%A1%D6%80%D5%B4%D5%B6%D5%AB_%D5%BB%D5%A5%D6%80%D5%B4%D5%A1%D5%BD%D5%BF%D5%AB%D5%B3%D5%A1%D5%B6 \"Մարդու մարմնի ջերմաստիճան – Armenian\")\n- [Italiano](https:\/\/it.wikipedia.org\/wiki\/Temperatura_corporea_umana \"Temperatura corporea umana – Italian\")\n- [Bahasa Melayu](https:\/\/ms.wikipedia.org\/wiki\/Suhu_badan_manusia \"Suhu badan manusia – Malay\")\n- [Polski](https:\/\/pl.wikipedia.org\/wiki\/Temperatura_cia%C5%82a_cz%C5%82owieka \"Temperatura ciała człowieka – Polish\")\n- [ไทย](https:\/\/th.wikipedia.org\/wiki\/%E0%B8%AD%E0%B8%B8%E0%B8%93%E0%B8%AB%E0%B8%A0%E0%B8%B9%E0%B8%A1%E0%B8%B4%E0%B8%9B%E0%B8%81%E0%B8%95%E0%B8%B4%E0%B8%82%E0%B8%AD%E0%B8%87%E0%B8%A3%E0%B9%88%E0%B8%B2%E0%B8%87%E0%B8%81%E0%B8%B2%E0%B8%A2%E0%B8%A1%E0%B8%99%E0%B8%B8%E0%B8%A9%E0%B8%A2%E0%B9%8C \"อุณหภูมิปกติของร่างกายมนุษย์ – Thai\")\n- [Türkçe](https:\/\/tr.wikipedia.org\/wiki\/%C4%B0nsan_v%C3%BCcut_s%C4%B1cakl%C4%B1%C4%9F%C4%B1 \"İnsan vücut sıcaklığı – Turkish\")\n- [Tiếng Việt](https:\/\/vi.wikipedia.org\/wiki\/Nhi%E1%BB%87t_%C4%91%E1%BB%99_c%C6%A1_th%E1%BB%83_con_ng%C6%B0%E1%BB%9Di \"Nhiệt độ cơ thể con người – Vietnamese\")\n- [中文](https:\/\/zh.wikipedia.org\/wiki\/%E4%BA%BA%E9%AB%94%E6%BA%AB%E5%BA%A6 \"人體溫度 – Chinese\")\n\n[Edit links](https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q16679262#sitelinks-wikipedia \"Edit interlanguage links\")\n\n- [Article](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature \"View the content page [c]\")\n- [Talk](https:\/\/en.wikipedia.org\/wiki\/Talk:Human_body_temperature \"Discuss improvements to the content page [t]\")\n\nEnglish\n\n- [Read](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature)\n- [Edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit \"Edit this page [e]\")\n- [View history](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=history \"Past revisions of this page [h]\")\n\nTools\n\nTools\n\nmove to sidebar\n\nhide\n\nActions\n\n- [Read](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature)\n- [Edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit \"Edit this page [e]\")\n- [View history](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=history)\n\nGeneral\n\n- [What links here](https:\/\/en.wikipedia.org\/wiki\/Special:WhatLinksHere\/Human_body_temperature \"List of all English Wikipedia pages containing links to this page [j]\")\n- [Related changes](https:\/\/en.wikipedia.org\/wiki\/Special:RecentChangesLinked\/Human_body_temperature \"Recent changes in pages linked from this page [k]\")\n- [Upload file](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_Upload_Wizard \"Upload files [u]\")\n- [Permanent link](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&oldid=1344460278 \"Permanent link to this revision of this page\")\n- [Page information](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=info \"More information about this page\")\n- [Cite this page](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CiteThisPage&page=Human_body_temperature&id=1344460278&wpFormIdentifier=titleform \"Information on how to cite this page\")\n- [Get shortened URL](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHuman_body_temperature)\n\nPrint\/export\n\n- [Download as PDF](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:DownloadAsPdf&page=Human_body_temperature&action=show-download-screen \"Download this page as a PDF file\")\n- [Printable version](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&printable=yes \"Printable version of this page [p]\")\n\nIn other projects\n\n- [Wikimedia Commons](https:\/\/commons.wikimedia.org\/wiki\/Category:Human_body_temperature)\n- [Wikidata item](https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q16679262 \"Structured data on this page hosted by Wikidata [g]\")\n\nAppearance\n\nmove to sidebar\n\nhide\n\nFrom Wikipedia, the free encyclopedia\n\nTypical temperature range found in humans\n\n|   |   |\n|---|---|\n| ![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/a\/ae\/Star_of_life.svg\/60px-Star_of_life.svg.png) | This article **needs more [reliable medical references](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\") for [verification](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Verifiability \"Wikipedia:Verifiability\") or relies too heavily on [primary sources](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Primary_sources \"Wikipedia:Primary sources\")**. Please review the contents of the article and [add the appropriate references](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit) if you can. Unsourced or poorly sourced material may be challenged and [removed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Verifiability#Burden_of_evidence \"Wikipedia:Verifiability\"). *Find sources:* [\"Human body temperature\"](https:\/\/www.google.com\/search?as_eq=wikipedia&q=%22Human+body+temperature%22) – [news](https:\/\/www.google.com\/search?tbm=nws&q=%22Human+body+temperature%22+-wikipedia&tbs=ar:1) **·** [newspapers](https:\/\/www.google.com\/search?&q=%22Human+body+temperature%22&tbs=bkt:s&tbm=bks) **·** [books](https:\/\/www.google.com\/search?tbs=bks:1&q=%22Human+body+temperature%22+-wikipedia) **·** [scholar](https:\/\/scholar.google.com\/scholar?q=%22Human+body+temperature%22) **·** [JSTOR](https:\/\/www.jstor.org\/action\/doBasicSearch?Query=%22Human+body+temperature%22&acc=on&wc=on) *(November 2022)* |\n\n|   |   |\n|---|---|\n| Temperature classification |   |\n|   |   |\n|   | [Core](https:\/\/en.wikipedia.org\/wiki\/Core_temperature#Core_temperature \"Core temperature\") (rectal, esophageal, etc.) |\n| [Hypothermia](https:\/\/en.wikipedia.org\/wiki\/Hypothermia \"Hypothermia\") | \\<35.0 °C (95.0 °F)[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Rosen-1) |\n| [Normal]() | 36\\.5–37.5 °C (97.7–99.5 °F)[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-pmid18788094-2)[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-3) |\n| [Fever](https:\/\/en.wikipedia.org\/wiki\/Fever \"Fever\") | \\>37.5 or 38.3 °C (99.5 or 100.9 °F)[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-NC08-4)[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-CC09-5) |\n| [Hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\") | \\>37.5 or 38.3 °C (99.5 or 100.9 °F)[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-NC08-4)[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-CC09-5) |\n| [Hyperpyrexia](https:\/\/en.wikipedia.org\/wiki\/Fever#Hyperpyrexia \"Fever\") | \\>40.0 or 41.0 °C (104.0 or 105.8 °F)[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-6)[\\[7\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-7) |\n| Note: The difference between fever and hyperthermia is the underlying mechanism. Different sources have different cut-offs for fever, hyperthermia and hyperpyrexia. |   |\n| [v](https:\/\/en.wikipedia.org\/wiki\/Template:HumanTemperature \"Template:HumanTemperature\") [t](https:\/\/en.wikipedia.org\/wiki\/Template_talk:HumanTemperature \"Template talk:HumanTemperature\") [e](https:\/\/en.wikipedia.org\/wiki\/Special:EditPage\/Template:HumanTemperature \"Special:EditPage\/Template:HumanTemperature\") |   |\n\n**Normal human body temperature** (**normothermia**, **euthermia**) is the typical [temperature](https:\/\/en.wikipedia.org\/wiki\/Temperature \"Temperature\") range found in [humans](https:\/\/en.wikipedia.org\/wiki\/Humans \"Humans\"). The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F).[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kar2008-8)[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-pmid_37669046-9)\n\nHuman body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the [body](https:\/\/en.wikipedia.org\/wiki\/Human_body \"Human body\") the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a [homeostatic](https:\/\/en.wikipedia.org\/wiki\/Homeostasis \"Homeostasis\") function known as [thermoregulation](https:\/\/en.wikipedia.org\/wiki\/Thermoregulation_in_humans \"Thermoregulation in humans\"), in which adjustment of temperature is triggered by the [central nervous system](https:\/\/en.wikipedia.org\/wiki\/Central_nervous_system \"Central nervous system\").\n\n## Methods of measurement\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=1 \"Edit section: Methods of measurement\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/9\/93\/Clinical_thermometer_38.7.JPG\/250px-Clinical_thermometer_38.7.JPG)](https:\/\/en.wikipedia.org\/wiki\/File:Clinical_thermometer_38.7.JPG)\n\nA [medical thermometer](https:\/\/en.wikipedia.org\/wiki\/Medical_thermometer \"Medical thermometer\") showing a temperature reading of 38.7 °C (101.7 °F)\n\nTaking a human's temperature is an initial part of a full [clinical examination](https:\/\/en.wikipedia.org\/wiki\/Clinical_examination \"Clinical examination\"). There are various types of [medical thermometers](https:\/\/en.wikipedia.org\/wiki\/Medical_thermometer \"Medical thermometer\"), as well as sites used for measurement, including:\n\n- Under the armpit (axillary temperature)\n- In the mouth (oral temperature)\n- In the [rectum](https:\/\/en.wikipedia.org\/wiki\/Rectum \"Rectum\") (rectal temperature)\n- In the ear (tympanic temperature)\n- On the skin of the forehead over the [temporal artery](https:\/\/en.wikipedia.org\/wiki\/Superficial_temporal_artery \"Superficial temporal artery\")\n- Using [heat flux sensors](https:\/\/en.wikipedia.org\/wiki\/Heat_flux_sensor \"Heat flux sensor\")\n\n### Variations\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=2 \"Edit section: Variations\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/2\/21\/Body_Temp_Variation.svg\/330px-Body_Temp_Variation.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:Body_Temp_Variation.svg)\n\nDiurnal variation in body temperature, ranging from about 37.5 °C (99.5 °F) from 10 a.m. to 6 p.m., and falling to about 36.4 °C (97.5 °F) from 2 a.m. to 6 a.m. (Based on figure in entry for 'Animal Heat' in 11th edition of the [Encyclopædia Britannica](https:\/\/en.wikipedia.org\/wiki\/Encyclop%C3%A6dia_Britannica \"Encyclopædia Britannica\"), 1910)\n\n[Temperature control](https:\/\/en.wikipedia.org\/wiki\/Thermoregulation_in_humans \"Thermoregulation in humans\") ([thermoregulation](https:\/\/en.wikipedia.org\/wiki\/Thermoregulation \"Thermoregulation\")) is a [homeostatic](https:\/\/en.wikipedia.org\/wiki\/Homeostatic \"Homeostatic\") mechanism that keeps the organism at optimum [operating temperature](https:\/\/en.wikipedia.org\/wiki\/Operating_temperature \"Operating temperature\"), as the temperature affects the rate of [chemical reactions](https:\/\/en.wikipedia.org\/wiki\/Chemical_reaction \"Chemical reaction\"). In [humans](https:\/\/en.wikipedia.org\/wiki\/Human \"Human\"), the average internal temperature is widely accepted to be 37 °C (98.6 °F), a \"normal\" temperature established in the 1800s. But newer studies show that average internal temperature for men and women is 36.4 °C (97.5 °F).[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-10) No person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's [circadian rhythm](https:\/\/en.wikipedia.org\/wiki\/Circadian_rhythm \"Circadian rhythm\"). The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors.[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly-11)\n\nIn addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.90 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day.\n\nNormal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F).[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Mac-12) This means that any oral temperature between 36.3 and 37.3 °C (97.3 and 99.1 °F) is likely to be normal.[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-13)\n\nThe normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F).[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kar2008-8)[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-pmid_37669046-9) In adults a review of the literature has found a wider range of 33.2–38.2 °C (91.8–100.8 °F) for normal temperatures, depending on the gender and location measured.[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-SundLevander2002-14)\n\nReported values vary depending on how it is measured: oral (under the tongue): 36.8 ± 0.4 °C (98.2 ± 0.7 °F),[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) internal ([rectal](https:\/\/en.wikipedia.org\/wiki\/Rectal \"Rectal\"), [vaginal](https:\/\/en.wikipedia.org\/wiki\/Vagina \"Vagina\")): 37.0 °C (98.6 °F).[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) A rectal or vaginal measurement taken directly inside the body cavity is typically slightly higher than oral measurement, and oral measurement is somewhat higher than skin measurement. Other places, such as under the arm or in the ear, produce different typical temperatures.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) While some people think of these averages as representing normal or ideal measurements, a wide range of temperatures has been found in healthy people.[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-CC09-5) The body temperature of a healthy person varies during the day by about 0.5 °C (0.9 °F) with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) Other circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the [nadir](https:\/\/en.wikipedia.org\/wiki\/Nadir#Medicine \"Nadir\"), is one of the primary markers for [circadian rhythms](https:\/\/en.wikipedia.org\/wiki\/Circadian_rhythm \"Circadian rhythm\"). The body temperature also changes when a person is hungry, sleepy, sick, or cold.\n\n### Natural rhythms\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=3 \"Edit section: Natural rhythms\")\\]\n\nBody temperature normally fluctuates over the day following [circadian rhythms](https:\/\/en.wikipedia.org\/wiki\/Circadian_rhythm \"Circadian rhythm\"), with the lowest levels around 4 a.m. and the highest in the late afternoon, between 4:00 and 6:00 p.m. (assuming the person sleeps at night and stays awake during the day).[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Mac-12)[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) Therefore, an oral temperature of 37.3 °C (99.1 °F) would, strictly speaking, be a normal, healthy temperature in the afternoon but not in the early morning.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) An individual's body temperature typically changes by about 0.5 °C (0.9 °F) between its highest and lowest points each day.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15)\n\nBody temperature is sensitive to many hormones, so women have a temperature rhythm that varies with the [menstrual cycle](https:\/\/en.wikipedia.org\/wiki\/Menstrual_cycle \"Menstrual cycle\"), called a *circamensal* rhythm.[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly-11)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] A woman's [basal body temperature](https:\/\/en.wikipedia.org\/wiki\/Basal_body_temperature \"Basal body temperature\") rises sharply after [ovulation](https:\/\/en.wikipedia.org\/wiki\/Ovulation \"Ovulation\"), as [estrogen](https:\/\/en.wikipedia.org\/wiki\/Estrogen \"Estrogen\") production decreases and [progesterone](https:\/\/en.wikipedia.org\/wiki\/Progesterone \"Progesterone\") increases. [Fertility awareness](https:\/\/en.wikipedia.org\/wiki\/Fertility_awareness \"Fertility awareness\") programs use this change to identify when a woman has ovulated to achieve or avoid [pregnancy](https:\/\/en.wikipedia.org\/wiki\/Pregnancy \"Pregnancy\"). During the [luteal phase](https:\/\/en.wikipedia.org\/wiki\/Luteal_phase \"Luteal phase\") of the menstrual cycle, both the lowest and the average temperatures are slightly higher than during other parts of the cycle. However, the amount that the temperature rises during each day is slightly lower than typical, so the highest temperature of the day is not very much higher than usual.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly1-16)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] [Hormonal contraceptives](https:\/\/en.wikipedia.org\/wiki\/Hormonal_contraceptive \"Hormonal contraceptive\") both suppress the circamensal rhythm and raise the typical body temperature by about 0.6 °C (1.1 °F).[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly-11)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\]\n\nTemperature also may vary with the change of [seasons](https:\/\/en.wikipedia.org\/wiki\/Season \"Season\") during each year. This pattern is called a *circannual* rhythm.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly1-16)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] Studies of seasonal variations have produced inconsistent results. People living in different climates may have different seasonal patterns.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIt has been found that physically active individuals have larger changes in body temperature throughout the day. Physically active people have been reported to have lower body temperatures than their less active peers in the early morning and similar or higher body temperatures later in the day.[\\[17\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Atkinson-17)\n\nWith increased age, both average body temperature and the amount of daily variability in the body temperature tend to decrease.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly1-16)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] Elderly people may have a decreased ability to generate body heat during a fever, so even a [somewhat elevated temperature](https:\/\/en.wikipedia.org\/wiki\/Low-grade_fever \"Low-grade fever\") can indicate a serious underlying cause in [geriatrics](https:\/\/en.wikipedia.org\/wiki\/Geriatrics \"Geriatrics\"). One study suggested that the average body temperature has also decreased since the 1850s.[\\[18\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-18) The study's authors believe the most likely explanation for the change is a reduction in inflammation at the population level due to decreased chronic infections and improved hygiene.[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-19)\n\n### Measurement methods\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=4 \"Edit section: Measurement methods\")\\]\n\n| Method | Women | Men |\n|---|---|---|\n| Oral | 33\\.2–38.1 °C (91.8–100.6 °F) | 35\\.7–37.7 °C (96.3–99.9 °F) |\n| Rectal | 36\\.8–37.1 °C (98.2–98.8 °F) | 36\\.7–37.5 °C (98.1–99.5 °F) |\n| Tympanic | 35\\.7–37.5 °C (96.3–99.5 °F) | 35\\.5–37.5 °C (95.9–99.5 °F) |\n| Axillary | 35\\.5–37.0 °C (95.9–98.6 °F) |   |\n\nDifferent methods used for measuring temperature produce different results. The temperature reading depends on which part of the body is being measured. The typical daytime temperatures among healthy adults are as follows:\n\n- Temperature in the rectum (rectal), vagina, or in the ear (tympanic) is about 37.5 °C (99.5 °F)[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Elert2005-20)\\[*[medical citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\]\n- Temperature in the mouth (oral) is about 36.8 °C (98.2 °F)[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Mac-12)\n- Temperature under the arm (axillary) is about 36.5 °C (97.7 °F)[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Elert2005-20)\\[*[medical citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\]\n\nGenerally, oral, rectal, gut, and core body temperatures, although slightly different, are well-correlated.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nOral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open. [Mouth breathing](https:\/\/en.wikipedia.org\/wiki\/Mouth_breathing \"Mouth breathing\"), cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures.[\\[21\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-21)\n\nEach measurement method also has different normal ranges depending on sex.[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-SundLevander2002-14)\n\n### Infrared thermometer\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=5 \"Edit section: Infrared thermometer\")\\]\n\nMain article: [Infrared thermometer](https:\/\/en.wikipedia.org\/wiki\/Infrared_thermometer \"Infrared thermometer\")\n\nAs of 2016, reviews of infrared thermometers have found them to be of variable accuracy.[\\[22\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-22) This includes tympanic infrared thermometers in children.[\\[23\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-23)\n\n### Variations due to outside factors\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=6 \"Edit section: Variations due to outside factors\")\\]\n\nSleep disturbances also affect temperatures. Normally, body temperature drops significantly at a person's normal bedtime and throughout the night. Short-term [sleep deprivation](https:\/\/en.wikipedia.org\/wiki\/Sleep_deprivation \"Sleep deprivation\") produces a higher temperature at night than normal, but long-term sleep deprivation appears to reduce temperatures.[\\[24\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-24) [Insomnia](https:\/\/en.wikipedia.org\/wiki\/Insomnia \"Insomnia\") and poor sleep quality are associated with smaller and later drops in body temperature.[\\[25\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-25) Similarly, waking up unusually early, sleeping in, [jet lag](https:\/\/en.wikipedia.org\/wiki\/Jet_lag \"Jet lag\") and changes to [shift work](https:\/\/en.wikipedia.org\/wiki\/Shift_work \"Shift work\") schedules may affect body temperature.\n\n## Concept\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=7 \"Edit section: Concept\")\\]\n\n### Fever\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=8 \"Edit section: Fever\")\\]\n\nMain article: [Fever](https:\/\/en.wikipedia.org\/wiki\/Fever \"Fever\")\n\nA temperature *setpoint* is the level at which the body attempts to maintain its temperature. When the setpoint is raised, the result is a fever. Most fevers are caused by [infectious disease](https:\/\/en.wikipedia.org\/wiki\/Infectious_disease \"Infectious disease\") and can be lowered, if desired, with [antipyretic](https:\/\/en.wikipedia.org\/wiki\/Antipyretic \"Antipyretic\") medications.\n\nAn early morning temperature higher than 37.3 °C (99.1 °F) or a late afternoon temperature higher than 37.7 °C (99.9 °F) is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) Lower thresholds are sometimes appropriate for elderly people.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) The normal daily temperature variation is typically 0.5 °C (0.90 °F), but can be greater among people recovering from a fever.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15)\n\nAn organism at optimum temperature is considered *afebrile*, meaning \"[without fever](https:\/\/en.wikipedia.org\/wiki\/Apyrexy \"Apyrexy\")\".[\\[26\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-26) If temperature is raised, but the setpoint is not raised, then the result is [hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\").\n\n### Hyperthermia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=9 \"Edit section: Hyperthermia\")\\]\n\nMain article: [Hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\")\n\nHyperthermia occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably. Hyperthermia at or above about 40 °C (104 °F) is a life-threatening medical emergency that requires immediate treatment. Common symptoms include headache, confusion, and fatigue. If sweating has resulted in dehydration, then the affected person may have dry, red skin.\n\nIn a medical setting, mild hyperthermia is commonly called *heat exhaustion* or *heat prostration*; severe hyperthermia is called *heat stroke*. Heatstroke may come on suddenly, but it usually follows the untreated milder stages. Treatment involves cooling and rehydrating the body; fever-reducing drugs are useless for this condition. This may be done by moving out of direct sunlight to a cooler and shaded environment, drinking water, removing clothing that might keep heat close to the body, or sitting in front of a fan. Bathing in tepid or cool water, or even just [washing the face](https:\/\/en.wikipedia.org\/wiki\/Face_washing \"Face washing\") and other exposed areas of the skin, can be helpful.\n\nWith fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers.\n\n### Hypothermia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=10 \"Edit section: Hypothermia\")\\]\n\nMain article: [Hypothermia](https:\/\/en.wikipedia.org\/wiki\/Hypothermia \"Hypothermia\")\n\nIn hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be [deliberately induced as a medical treatment](https:\/\/en.wikipedia.org\/wiki\/Therapeutic_hypothermia \"Therapeutic hypothermia\"). Symptoms usually appear when the body's core temperature drops by 1–2 °C (1.8–3.6 °F) below normal temperature.\n\n### Basal body temperature\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=11 \"Edit section: Basal body temperature\")\\]\n\nMain article: [Basal body temperature](https:\/\/en.wikipedia.org\/wiki\/Basal_body_temperature \"Basal body temperature\")\n\nBasal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature. In women, temperature differs at various points in the [menstrual cycle](https:\/\/en.wikipedia.org\/wiki\/Menstrual_cycle \"Menstrual cycle\"), and this can be used in the long term to track ovulation both to aid conception or avoid pregnancy. This process is called [fertility awareness](https:\/\/en.wikipedia.org\/wiki\/Fertility_awareness \"Fertility awareness\").\n\n### Core temperature\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=12 \"Edit section: Core temperature\")\\]\n\nCore temperature, also called core body temperature, is the operating temperature of an [organism](https:\/\/en.wikipedia.org\/wiki\/Organism \"Organism\"), specifically in deep structures of the body such as the [liver](https:\/\/en.wikipedia.org\/wiki\/Liver \"Liver\"), in comparison to temperatures of peripheral tissues. Core temperature is normally maintained within a narrow range so that essential enzymatic reactions can occur. Significant core temperature elevation ([hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\")) or depression ([hypothermia](https:\/\/en.wikipedia.org\/wiki\/Hypothermia \"Hypothermia\")) over more than a brief period of time is fatal.\n\nTemperature examination in the [heart](https:\/\/en.wikipedia.org\/wiki\/Heart \"Heart\"), using a catheter, is the traditional [gold standard](https:\/\/en.wikipedia.org\/wiki\/Gold_standard_\\(test\\) \"Gold standard (test)\") measurement used to estimate core temperature (oral temperature is affected by hot or cold drinks, ambient temperature fluctuations as well as mouth-breathing). Since catheters are highly invasive, the generally accepted alternative for measuring core body temperature is through rectal measurements. Rectal temperature is expected to be approximately 1 °F (0.56 °C) higher than an oral temperature taken on the same person at the same time. Ear thermometers measure temperature from the [tympanic membrane](https:\/\/en.wikipedia.org\/wiki\/Tympanic_membrane \"Tympanic membrane\") using [infrared](https:\/\/en.wikipedia.org\/wiki\/Infrared \"Infrared\") sensors and also aim to measure core body temperature, since the blood supply of this membrane is directly shared with the [brain](https:\/\/en.wikipedia.org\/wiki\/Brain \"Brain\"). However, this method of measuring body temperature is not as accurate as rectal measurement and has a low sensitivity for fever, failing to determine three or four out of every ten fever measurements in children.[\\[27\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Dodd-27) Ear temperature measurement may be acceptable for observing trends in body temperature but is less useful in consistently identifying and diagnosing fever.\n\nUntil recently, direct measurement of core body temperature required either an ingestible device or surgical insertion of a probe. Therefore, a variety of indirect methods have commonly been used as the preferred alternative to these more accurate albeit more invasive methods. The [rectal](https:\/\/en.wikipedia.org\/wiki\/Rectum \"Rectum\") or [vaginal](https:\/\/en.wikipedia.org\/wiki\/Vagina \"Vagina\") temperature is generally considered to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible [thermistors](https:\/\/en.wikipedia.org\/wiki\/Thermistor \"Thermistor\") in [capsule](https:\/\/en.wikipedia.org\/wiki\/Capsule_\\(pharmacy\\) \"Capsule (pharmacy)\") form were produced, allowing the temperature inside the [digestive tract](https:\/\/en.wikipedia.org\/wiki\/Digestive_tract \"Digestive tract\") to be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement.[\\[28\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-SciDirect-28) More recently, a new method using [heat flux sensors](https:\/\/en.wikipedia.org\/wiki\/Heat_flux_sensor \"Heat flux sensor\") have been developed. Several research papers show that its accuracy is similar to the invasive methods.[\\[29\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-29)[\\[30\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-30)[\\[31\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-31)\n\n### Internal variation\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=13 \"Edit section: Internal variation\")\\]\n\nMeasurement within the body finds internal variation temperatures as different as 21.5 °C (70.7 °F) for the [radial artery](https:\/\/en.wikipedia.org\/wiki\/Radial_artery \"Radial artery\") and 31.1 °C (88.0 °F) for the [brachial artery](https:\/\/en.wikipedia.org\/wiki\/Brachial_artery \"Brachial artery\").[\\[32\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32) It has been observed that \"chaos\" has been \"introduced into physiology by the fictitious assumption of a constant blood temperature\".[\\[32\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32)\n\n## Temperature variation\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=14 \"Edit section: Temperature variation\")\\]\n\n|   |   |\n|---|---|\n| [![icon](https:\/\/upload.wikimedia.org\/wikipedia\/en\/thumb\/9\/99\/Question_book-new.svg\/60px-Question_book-new.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:Question_book-new.svg) | This section **needs additional citations for [verification](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Verifiability \"Wikipedia:Verifiability\")**. Please help [improve this article](https:\/\/en.wikipedia.org\/wiki\/Special:EditPage\/Human_body_temperature \"Special:EditPage\/Human body temperature\") by [adding citations to reliable sources](https:\/\/en.wikipedia.org\/wiki\/Help:Referencing_for_beginners \"Help:Referencing for beginners\") in this section. Unsourced material may be challenged and removed. *(July 2014)* *([Learn how and when to remove this message](https:\/\/en.wikipedia.org\/wiki\/Help:Maintenance_template_removal \"Help:Maintenance template removal\"))* |\n\n### Hot\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=15 \"Edit section: Hot\")\\]\n\n- 44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F).[\\[33\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-33)[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-34)\n- 43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur.\n- 42 °C (107.6 °F) – Subject may turn red. They may become comatose, be in severe delirium, and convulsions can occur.\n- 41 °C (105.8 °F) – ([Medical emergency](https:\/\/en.wikipedia.org\/wiki\/Medical_emergency \"Medical emergency\")) – Fainting, severe headache, dizziness, confusion, hallucinations, delirium, and drowsiness can occur. There may also be [palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitations \"Palpitations\") and breathlessness.\n- 40 °C (104 °F) – Fainting, dehydration, weakness, headache, breathlessness, and dizziness may occur as well as profuse sweating.\n- 39 °C (102.2 °F) – Severe sweating, and red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer convulsions at this temperature.\n- 38 °C (100.4 °F) – (Classed as [hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\") if not caused by a [fever](https:\/\/en.wikipedia.org\/wiki\/Fever \"Fever\")) – Feeling hot, sweating, feeling thirsty, feeling very uncomfortable.\n- 37\\.6 °C (99.7 °F) — Classed as a slight fever. May lose appetite, feeling hot, feeling uncomfortable, feeling thirsty.\n\n### Normal\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=16 \"Edit section: Normal\")\\]\n\n- 36\\.5–37.5 °C (97.7–99.5 °F) is a typically reported range for normal body temperature.[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kar2008-8)\n\n### Cold\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=17 \"Edit section: Cold\")\\]\n\n- 35\\.5 °C (95.9 °F) – Feeling cold, mild to moderate shivering. This can be a normal body temperature for sleeping.\n- 35 °C (95 °F) – Threshold for [hypothermia](https:\/\/en.wikipedia.org\/wiki\/Hypothermia \"Hypothermia\"). Intense shivering, numbness and bluish\/grayness of the skin. There is the possibility of heart irritability.\n- 34 °C (93.2 °F) – Severe shivering, loss of movement of fingers, blueness, and confusion. Some behavioral changes may take place.\n- 33 °C (91.4 °F) – Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heartbeat, shallow breathing. Shivering may stop. The subject may be unresponsive to certain stimuli.\n- 32 °C (89.6 °F) – ([Medical emergency](https:\/\/en.wikipedia.org\/wiki\/Medical_emergency \"Medical emergency\")) – Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent. Reflex may be absent or very slight.\n- 31 °C (87.8 °F) – Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems.\n- 28 °C (82.4 °F) – Severe heart rhythm disturbances are likely and breathing may stop at any time. The person may appear to be dead.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n- 24–26 °C (75.2–78.8 °F) or less – Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures lower than 12.7 °C (54.9 °F).[\\[35\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-35) The lowest recorded core temperature from a patient with accidental hypothermia who survived without neurological [sequelae](https:\/\/en.wikipedia.org\/wiki\/Sequela \"Sequela\") is 11.8 °C (53.2 °F).[\\[36\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-36)\n\nThere are non-verbal corporal cues that can hint at an individual experiencing a low body temperature, which can be used for those with [dysphasia](https:\/\/en.wikipedia.org\/wiki\/Dysphasia \"Dysphasia\") or infants.[\\[37\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-37) Examples of non-[verbal](https:\/\/en.wiktionary.org\/wiki\/verbal \"wikt:verbal\") cues of [coldness](https:\/\/en.wikipedia.org\/wiki\/Coldness \"Coldness\") include stillness and being lethargic, unusual paleness of skin among light-skinned people, and, among males, shrinkage, and contraction of the [scrotum](https:\/\/en.wikipedia.org\/wiki\/Scrotum \"Scrotum\").[\\[38\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-38)\n\n## Effect of environment\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=18 \"Edit section: Effect of environment\")\\]\n\nEnvironmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The [psychrometric temperature](https:\/\/en.wikipedia.org\/wiki\/Psychrometrics \"Psychrometrics\"), of which the [wet-bulb temperature](https:\/\/en.wikipedia.org\/wiki\/Wet-bulb_temperature \"Wet-bulb temperature\") is the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value consistent with human life.\n\nA 2022 study on the effect of heat on young people found that the critical wet-bulb temperature at which heat stress can no longer be compensated, Twb,crit, in young, healthy adults performing tasks at modest metabolic rates mimicking basic activities of daily life was much lower than the 35 °C (95 °F) usually assumed, at about 30.55 °C (86.99 °F) in 36–40 °C (97–104 °F) humid environments, but progressively decreased in hotter, dry ambient environments.[\\[39\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-vecellio-39)[\\[40\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-timperley-40)\n\nAt low temperatures the body thermoregulates by generating heat, but this becomes unsustainable at extremely low temperatures.\n\n## Historical understanding\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=19 \"Edit section: Historical understanding\")\\]\n\nIn the 19th century, most books quoted \"blood heat\" as 98 °F, until a study published the mean (but not the variance) of a large sample as 36.88 °C (98.38 °F).[\\[41\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-41) Subsequently, that mean was widely quoted as \"37 °C or 98.4 °F\"[\\[42\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-42)[\\[43\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-43) until editors realized 37 °C is equal to 98.6 °F, not 98.4 °F. The 37 °C value was set by German physician [Carl Reinhold August Wunderlich](https:\/\/en.wikipedia.org\/wiki\/Carl_Reinhold_August_Wunderlich \"Carl Reinhold August Wunderlich\") in his 1868 book,[\\[44\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-44) which put temperature charts into widespread clinical use.[\\[45\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-45) Dictionaries and other sources\\[*[which?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Avoid_weasel_words \"Wikipedia:Avoid weasel words\")*\\] that quoted these averages did add the word \"about\" to show that there is some variance, but generally did not state how wide the variance is.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n## References\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=20 \"Edit section: References\")\\]\n\n1. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Rosen_1-0)**\n   Marx J (2006). *Rosen's emergency medicine : concepts and clinical practice* (6th ed.). Philadelphia: Mosby\/Elsevier. p. 2239. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n   \n   [978-0-323-02845-5](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-323-02845-5 \"Special:BookSources\/978-0-323-02845-5\")\n   \n   . [OCLC](https:\/\/en.wikipedia.org\/wiki\/OCLC_\\(identifier\\) \"OCLC (identifier)\") [58533794](https:\/\/search.worldcat.org\/oclc\/58533794).\n2. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-pmid18788094_2-0)**\n   Hutchison JS, Ward RE, Lacroix J, Hébert PC, Barnes MA, Bohn DJ, et al. (June 2008). \"Hypothermia therapy after traumatic brain injury in children\". *The New England Journal of Medicine*. **358** (23): 2447–56\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1056\/NEJMoa0706930](https:\/\/doi.org\/10.1056%2FNEJMoa0706930). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18525042](https:\/\/pubmed.ncbi.nlm.nih.gov\/18525042).\n3. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-3)**\n   Pryor JA, Prasad AS (2008). [*Physiotherapy for Respiratory and Cardiac Problems: Adults and Paediatrics*](https:\/\/books.google.ca\/books?id=5n9fseWPLowC&pg=PA8). Elsevier Health Sciences. p. 8. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n   \n   [978-0702039744](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0702039744 \"Special:BookSources\/978-0702039744\")\n   \n   . \"Body temperature is maintained within the range 36.5-37.5 °C. It is lowest in the early morning and highest in the afternoon.\"\n4. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-NC08_4-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-NC08_4-1)\n   Axelrod YK, Diringer MN (May 2008). \"Temperature management in acute neurologic disorders\". *Neurologic Clinics*. **26** (2): 585–603, xi. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.ncl.2008.02.005](https:\/\/doi.org\/10.1016%2Fj.ncl.2008.02.005). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18514828](https:\/\/pubmed.ncbi.nlm.nih.gov\/18514828).\n5. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-CC09_5-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-CC09_5-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-CC09_5-2)\n   Laupland KB (July 2009). \"Fever in the critically ill medical patient\". *Critical Care Medicine*. **37** (7 Suppl): S273-8. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1097\/CCM.0b013e3181aa6117](https:\/\/doi.org\/10.1097%2FCCM.0b013e3181aa6117). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [19535958](https:\/\/pubmed.ncbi.nlm.nih.gov\/19535958).\n6. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-6)**\n   Grunau BE, Wiens MO, Brubacher JR (September 2010). \"Dantrolene in the treatment of MDMA-related hyperpyrexia: a systematic review\". *Cjem*. **12** (5): 435–42\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1017\/s1481803500012598](https:\/\/doi.org\/10.1017%2Fs1481803500012598). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [20880437](https:\/\/pubmed.ncbi.nlm.nih.gov\/20880437). \"Dantrolene may also be associated with improved survival and reduced complications, especially in patients with extreme (≥ 42 °C) or severe (≥ 40 °C) hyperpyrexia\"\n7. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-7)**\n   Sharma HS, ed. (2007). [*Neurobiology of Hyperthermia*](https:\/\/books.google.com\/books?id=Vk1UTlmEwrQC&pg=485#v=onepage&q=hyperpyrexia%20core%20temperature&f=false) (1st ed.). Elsevier. pp. 175–177, 485. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n   \n   [9780080549996](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/9780080549996 \"Special:BookSources\/9780080549996\")\n   \n   . Retrieved 19 November 2016. \"Despite the myriad of complications associated with heat illness, an elevation of core temperature above 41.0 °C (often referred to as fever or hyperpyrexia) is the most widely recognized symptom of this syndrome.\"\n8. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kar2008_8-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kar2008_8-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kar2008_8-2)\n   Hutchison, James S.; et al. (June 2008). [\"Hypothermia therapy after traumatic brain injury in children\"](https:\/\/doi.org\/10.1056%2FNEJMoa0706930). *New England Journal of Medicine*. **358** (23): 2447–2456\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1056\/NEJMoa0706930](https:\/\/doi.org\/10.1056%2FNEJMoa0706930). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18525042](https:\/\/pubmed.ncbi.nlm.nih.gov\/18525042). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [46833](https:\/\/api.semanticscholar.org\/CorpusID:46833). \"We hypothesized that, as compared with normothermia (36.5 to 37.5°C), treatment with hypothermia...\"\n9. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-pmid_37669046_9-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-pmid_37669046_9-1)\n   Ley, C; Heath, F; Hastie, T; Gao, Z; Protsiv, M; Parsonnet, J (5 September 2023). [\"Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC10481327). *JAMA Internal Medicine*. **183** (10): 1128–1135\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1001\/jamainternmed.2023.4291](https:\/\/doi.org\/10.1001%2Fjamainternmed.2023.4291). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [10481327](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC10481327). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [37669046](https:\/\/pubmed.ncbi.nlm.nih.gov\/37669046).\n10. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-10)**\n    Weintraub, Karen (April 2020). [\"Are Human Body Temperatures Cooling Down?\"](https:\/\/www.scientificamerican.com\/article\/are-human-body-temperatures-cooling-down\/). *Scientific American*. Retrieved 10 March 2022.\n11. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly_11-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly_11-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly_11-2)\n    Kelly, Greg S. (March 2007). [\"Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease\"](https:\/\/web.archive.org\/web\/20170809134435\/http:\/\/altmedrev.com\/publications\/12\/1\/49.pdf) (PDF). *Alternative Medicine Review*. **12** (1): 49–62\\. [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [17397267](https:\/\/pubmed.ncbi.nlm.nih.gov\/17397267). Archived from [the original](http:\/\/www.altmedrev.com\/publications\/12\/1\/49.pdf) (PDF) on 2017-08-09. Retrieved 2016-12-28.\n12. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Mac_12-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Mac_12-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Mac_12-2)\n    Mackowiak, Philip A.; Wasserman, Steven S.; Levine, Myron M. (1992-09-23). \"A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich\". *Journal of the American Medical Association*. **268** (12): 1578–1580\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1001\/jama.1992.03490120092034](https:\/\/doi.org\/10.1001%2Fjama.1992.03490120092034). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [1302471](https:\/\/pubmed.ncbi.nlm.nih.gov\/1302471).\n13. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-13)**\n    Del Bene, Victor E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.), [\"Temperature\"](https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK331\/), *Clinical Methods: The History, Physical, and Laboratory Examinations* (3rd ed.), Boston: Butterworths, [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n    \n    [978-0-409-90077-4](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-409-90077-4 \"Special:BookSources\/978-0-409-90077-4\")\n    \n    , [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [21250173](https:\/\/pubmed.ncbi.nlm.nih.gov\/21250173), retrieved 2023-02-15\n    \n    `{{citation}}`: CS1 maint: work parameter with ISBN ([link](https:\/\/en.wikipedia.org\/wiki\/Category:CS1_maint:_work_parameter_with_ISBN \"Category:CS1 maint: work parameter with ISBN\"))\n14. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SundLevander2002_14-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SundLevander2002_14-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SundLevander2002_14-2)\n    Sund-Levander, Märtha; Forsberg, Christina; Wahren, Lis Karen (2002). \"Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review\". *Scandinavian Journal of Caring Sciences*. **16** (2): 122–8\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1046\/j.1471-6712.2002.00069.x](https:\/\/doi.org\/10.1046%2Fj.1471-6712.2002.00069.x). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [12000664](https:\/\/pubmed.ncbi.nlm.nih.gov\/12000664).\n15. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-6) [***h***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-7) [***i***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-8) [***j***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-9)\n    Longo, Dan L., ed. (2011). [*Harrison's principles of internal medicine*](https:\/\/web.archive.org\/web\/20120429231736\/http:\/\/www.accessmedicine.com\/resourceTOC.aspx?resourceID=4) (18th ed.). New York: McGraw-Hill. p. 142. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n    \n    [978-0-07-174889-6](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-07-174889-6 \"Special:BookSources\/978-0-07-174889-6\")\n    \n    . Archived from [the original](http:\/\/accessmedicine.com\/resourceTOC.aspx?resourceID=4) on 2012-04-29. Retrieved 2012-03-16.\n16. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly1_16-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly1_16-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly1_16-2)\n    Kelly, Greg S. (December 2006). [\"Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging\"](https:\/\/web.archive.org\/web\/20170808231722\/http:\/\/altmedrev.com\/publications\/11\/4\/278.pdf) (PDF). *Alternative Medicine Review*. **11** (4): 278–93\\. [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [17176167](https:\/\/pubmed.ncbi.nlm.nih.gov\/17176167). Archived from [the original](http:\/\/www.altmedrev.com\/publications\/11\/4\/278.pdf) (PDF) on 2017-08-08. Retrieved 2016-12-28.\n17. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Atkinson_17-0)**\n    Atkinson, G.; Coldwells, A.; Reilly, T.; Waterhouse, J. (January 1993). \"A comparison of circadian rhythms in work performance between physically active and inactive subjects\". *Ergonomics*. **36** (1–3\\): 273–281\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1080\/00140139308967882](https:\/\/doi.org\/10.1080%2F00140139308967882). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [8440222](https:\/\/pubmed.ncbi.nlm.nih.gov\/8440222).\n18. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-18)**\n    Katz, Brigit (16 January 2020). [\"Human Body Temperature Is Getting Cooler, Study Finds\"](https:\/\/www.smithsonianmag.com\/smart-news\/human-body-temperature-getting-cooler-study-finds-180974006\/). *[Smithsonian](https:\/\/en.wikipedia.org\/wiki\/Smithsonian_\\(magazine\\) \"Smithsonian (magazine)\")*. Retrieved 22 January 2020.\n19. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-19)**\n    Protsiv, Myroslava; Ley, Catherine; Lankester, Joanna; Hastie, Trevor; [Parsonnet, Julie](https:\/\/en.wikipedia.org\/wiki\/Julie_Parsonnet \"Julie Parsonnet\") (2020-01-07). Jit, Mark; Franco, Eduardo; Waalen, Jill; Rühli, Frank (eds.). [\"Decreasing human body temperature in the United States since the Industrial Revolution\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6946399). *eLife*. **9** e49555. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.7554\/eLife.49555](https:\/\/doi.org\/10.7554%2FeLife.49555). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [2050-084X](https:\/\/search.worldcat.org\/issn\/2050-084X). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [6946399](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6946399). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [31908267](https:\/\/pubmed.ncbi.nlm.nih.gov\/31908267).\n20. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Elert2005_20-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Elert2005_20-1)\n    Wong, Lena (1997). Elert, Glenn (ed.). [\"Temperature of a healthy human (body temperature)\"](https:\/\/hypertextbook.com\/facts\/1997\/LenaWong.shtml). *The Physics Factbook*. Retrieved 2022-01-25.\n21. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-21)**\n    Newman, B. H.; Martin, C. A. (October 2001). [\"The effect of hot beverages, cold beverages, and chewing gum on oral temperature\"](https:\/\/doi.org\/10.1046%2Fj.1537-2995.2001.41101241.x). *Transfusion*. **41** (10): 1241–1243\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1046\/j.1537-2995.2001.41101241.x](https:\/\/doi.org\/10.1046%2Fj.1537-2995.2001.41101241.x). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [0041-1132](https:\/\/search.worldcat.org\/issn\/0041-1132). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [11606822](https:\/\/pubmed.ncbi.nlm.nih.gov\/11606822). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [24681501](https:\/\/api.semanticscholar.org\/CorpusID:24681501).\n22. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-22)**\n    Kiekkas, P; Stefanopoulos, N; Bakalis, N; Kefaliakos, A; Karanikolas, M (April 2016). \"Agreement of infrared temporal artery thermometry with other thermometry methods in adults: systematic review\". *Journal of Clinical Nursing*. **25** (7–8\\): 894–905\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1111\/jocn.13117](https:\/\/doi.org\/10.1111%2Fjocn.13117). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [26994990](https:\/\/pubmed.ncbi.nlm.nih.gov\/26994990).\n23. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-23)**\n    Zhen, C; Xia, Z; Long, L; Pu, Y (October 2014). \"Accuracy of infrared ear thermometry in children: a meta-analysis and systematic review\". *Clinical Pediatrics*. **53** (12): 1158–65\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1177\/0009922814536774](https:\/\/doi.org\/10.1177%2F0009922814536774). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [24879119](https:\/\/pubmed.ncbi.nlm.nih.gov\/24879119). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [24982111](https:\/\/api.semanticscholar.org\/CorpusID:24982111).\n24. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-24)**\n    Paprocki, Jonathan (2012-12-18). [\"Sleep deprivation disrupts regulation of body heat\"](https:\/\/sleepeducation.org\/sleep-deprivation-disrupts-regulation-body-heat\/). *Sleep Education*. Retrieved 2023-02-15.\n25. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-25)**\n    Lack, Leon C.; Gradisar, Michael; Van Someren, Eus J. W.; Wright, Helen R.; Lushington, Kurt (August 2008). \"The relationship between insomnia and body temperatures\". *Sleep Medicine Reviews*. **12** (4): 307–317\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.smrv.2008.02.003](https:\/\/doi.org\/10.1016%2Fj.smrv.2008.02.003). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [1087-0792](https:\/\/search.worldcat.org\/issn\/1087-0792). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18603220](https:\/\/pubmed.ncbi.nlm.nih.gov\/18603220).\n26. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-26)**\n    [\"Define Afebrile\"](https:\/\/www.dictionary.com\/browse\/afebrile).\n27. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Dodd_27-0)**\n    Dodd, Susanna R.; Lancaster, Gillian A.; Craig, Jean V.; Smyth, Rosalind L.; Williamson, Paula R. (April 2006). \"In a systematic review, infrared ear thermometry for fever diagnosis in children finds poor sensitivity\". *Journal of Clinical Epidemiology*. **59** (4): 354–7\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.jclinepi.2005.10.004](https:\/\/doi.org\/10.1016%2Fj.jclinepi.2005.10.004). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [16549256](https:\/\/pubmed.ncbi.nlm.nih.gov\/16549256).\n28. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SciDirect_28-0)**\n    McKenzie, Jack E.; Osgood, David W. (2004). \"Validation of a new telemetric core temperature monitor\". *Journal of Thermal Biology*. **29** (7–8\\): 605. [Bibcode](https:\/\/en.wikipedia.org\/wiki\/Bibcode_\\(identifier\\) \"Bibcode (identifier)\"):[2004JTBio..29..605M](https:\/\/ui.adsabs.harvard.edu\/abs\/2004JTBio..29..605M). [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.jtherbio.2004.08.020](https:\/\/doi.org\/10.1016%2Fj.jtherbio.2004.08.020).\n29. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-29)**\n    Nidermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel (January 2014). [\"Prediction of Human Core Body Temperature Using Non-Invasive Measurement Methods\"](https:\/\/www.dora.lib4ri.ch\/empa\/islandora\/object\/empa%3A6081). *International Journal of Biometeorology*. **58** (1): 7–15\\. [Bibcode](https:\/\/en.wikipedia.org\/wiki\/Bibcode_\\(identifier\\) \"Bibcode (identifier)\"):[2014IJBm...58....7N](https:\/\/ui.adsabs.harvard.edu\/abs\/2014IJBm...58....7N). [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1007\/s00484-013-0687-2](https:\/\/doi.org\/10.1007%2Fs00484-013-0687-2). [hdl](https:\/\/en.wikipedia.org\/wiki\/Hdl_\\(identifier\\) \"Hdl (identifier)\"):[20\\.500.11850\/80468](https:\/\/hdl.handle.net\/20.500.11850%2F80468). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [23760405](https:\/\/pubmed.ncbi.nlm.nih.gov\/23760405). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [11772946](https:\/\/api.semanticscholar.org\/CorpusID:11772946).\n30. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-30)**\n    Mendt, Stefan; Maggioni, Martina Ana; Nordine, Michael; Steinach, Mathias; Opatz, Oliver; Belavy, Daniel; Felsenberg, Dieter; Koch, Joachim; Shang, Peng; Hanns-Christian, Gunga; Stahn, Alexander (2017). \"Circadian Rhythms in Bed Rest: Monitoring Core Body Temperature via Heat-Flux Approach Is Superior to Skin Surface Temperature\". *Chronobiology International*. **34** (5): 666–676\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1080\/07420528.2016.1224241](https:\/\/doi.org\/10.1080%2F07420528.2016.1224241). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [27726448](https:\/\/pubmed.ncbi.nlm.nih.gov\/27726448). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [205581198](https:\/\/api.semanticscholar.org\/CorpusID:205581198).\n31. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-31)**\n    Uth, Marc-Florian; Koch, Jochim; Sattler, Frank (2016). [\"Body Core Temperature Sensing: Challenges and New Sensor Technologies\"](https:\/\/doi.org\/10.1016%2Fj.proeng.2016.11.154). *Procedia Engineering*. **168**: 89–92\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.proeng.2016.11.154](https:\/\/doi.org\/10.1016%2Fj.proeng.2016.11.154).\n32. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-1)\n    Bazett, H. C.; Love, L.; Newton, M.; Eisenberg, L.; Day, R.; Forster, R. (1948). \"Temperature Changes in Blood Flowing in Arteries and Veins in Man\". *Journal of Applied Physiology*. **1** (1): 3–19\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1152\/jappl.1948.1.1.3](https:\/\/doi.org\/10.1152%2Fjappl.1948.1.1.3). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [8750-7587](https:\/\/search.worldcat.org\/issn\/8750-7587). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18887571](https:\/\/pubmed.ncbi.nlm.nih.gov\/18887571).\n33. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-33)** Chudler, Eric H. [\"Biological Rhythms\"](http:\/\/faculty.washington.edu\/chudler\/clock.html), *Neuroscience for Kids*, faculty.washington.edu\n34. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-34)** [temperature registered more than 115.7\"](https:\/\/news.google.com\/newspapers?id=y4IwAAAAIBAJ&sjid=t0QDAAAAIBAJ&pg=4281,2822445&dq=115.7+degrees&hl=en), *Bulletin Journal*, August 7, 1980\n35. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-35)**\n    [\"2-latek z Polski rekordzistą. Przeżył wychłodzenie poniżej 12 st. C.\"](https:\/\/dzienniknaukowy.pl\/zdrowie\/2-latek-z-polski-rekordzista-przezyl-wychlodzenie-ponizej-12-st-c) *Dziennik Naukowy* (in Polish). 5 December 2014. Retrieved 23 September 2022.\n36. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-36)**\n    Mroczek, T.; Gladki, M.; Skalski, J. (26 June 2020). [\"Successful resuscitation from accidental hypothermia of 11.8°C: where is the lower bound for human beings?\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC7886275). *European Journal of Cardio-Thoracic Surgery*. **58** (5): 1091–1092\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1093\/ejcts\/ezaa159](https:\/\/doi.org\/10.1093%2Fejcts%2Fezaa159). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [7886275](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC7886275). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [33084865](https:\/\/pubmed.ncbi.nlm.nih.gov\/33084865).\n37. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-37)** Tomita, K., et al. \"Examination of factors affecting the intraoral perception of object size: A preliminary study.\" Journal of oral rehabilitation 44.4 (2017): 237–243.\n38. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-38)** Al-Tubaikh, Jarrah Ali. \"Infectious Diseases and Tropical Medicine.\" Internal Medicine. Springer, Cham, 2017. 441–493.\n39. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-vecellio_39-0)**\n    Vecellio, Daniel J.; Wolf, S. Tony; Cottle, Rachel M.; Kenney, W. Larry (2022-02-01). [\"Evaluating the 35°C wet-bulb temperature adaptability threshold for young, healthy subjects (PSU HEAT Project)\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC8799385). *Journal of Applied Physiology*. **132** (2): 340–345\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1152\/japplphysiol.00738.2021](https:\/\/doi.org\/10.1152%2Fjapplphysiol.00738.2021). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [8750-7587](https:\/\/search.worldcat.org\/issn\/8750-7587). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [8799385](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC8799385). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [34913738](https:\/\/pubmed.ncbi.nlm.nih.gov\/34913738).\n40. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-timperley_40-0)**\n    Timperley, Jocelyn (31 July 2022). [\"Why you need to worry about the 'wet-bulb temperature'\"](https:\/\/www.theguardian.com\/science\/2022\/jul\/31\/why-you-need-to-worry-about-the-wet-bulb-temperature). *The Guardian*.\n41. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-41)** [Inwit Publishing, Inc. and Inwit, LLC – Writings, Links and Software Demonstrations – A Fahrenheit–Celsius Activity](https:\/\/web.archive.org\/web\/20110713052807\/http:\/\/www.inwit.com\/inwit\/writings\/fahrenheitcelsiusactivity.html), inwit.com\n42. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-42)** *[Oxford Dictionary of English](https:\/\/en.wikipedia.org\/wiki\/Oxford_Dictionary_of_English \"Oxford Dictionary of English\")*, 2010 edition, entry on \"blood heat\"\n43. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-43)** *[Collins English Dictionary](https:\/\/en.wikipedia.org\/wiki\/Collins_English_Dictionary \"Collins English Dictionary\")*, 1979 edition, entry on [\"blood heat\"](https:\/\/www.collinsdictionary.com\/us\/dictionary\/english\/blood-heat)\n44. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-44)**\n    Wunderlich, Carl Reinhold August (1868). [*Das Verhalten der Eigenwärme in Krankheiten*](https:\/\/archive.org\/details\/dasverhaltender00wundgoog) \\[*The behavior of the self-warmth in diseases*\\]. Leipzig: O. Wigand.\n    \n    ; its 1871 2nd edition translated into English and published with the title [*On the temperature in diseases: a manual of medical thermometry*](https:\/\/archive.org\/details\/ontemperaturein01wundgoog).\n45. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-45)** Fischetti, Mark (2018), \"Graphic Science: Goodbye, 98.6\", *Scientific American*, vol. 319, no. 6 (December)\n\n![](https:\/\/en.wikipedia.org\/wiki\/Special:CentralAutoLogin\/start?useformat=desktop&type=1x1&usesul3=1)\n\nRetrieved from \"<https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&oldid=1344460278>\"\n\n[Categories](https:\/\/en.wikipedia.org\/wiki\/Help:Category \"Help:Category\"):\n\n- [Human physiology](https:\/\/en.wikipedia.org\/wiki\/Category:Human_physiology \"Category:Human physiology\")\n- [Medical terminology](https:\/\/en.wikipedia.org\/wiki\/Category:Medical_terminology \"Category:Medical terminology\")\n- [Temperature](https:\/\/en.wikipedia.org\/wiki\/Category:Temperature \"Category:Temperature\")\n- [Physical examination](https:\/\/en.wikipedia.org\/wiki\/Category:Physical_examination \"Category:Physical examination\")\n- [Medical signs](https:\/\/en.wikipedia.org\/wiki\/Category:Medical_signs \"Category:Medical signs\")\n- [Thermoregulation](https:\/\/en.wikipedia.org\/wiki\/Category:Thermoregulation \"Category:Thermoregulation\")\n- [Thermometers](https:\/\/en.wikipedia.org\/wiki\/Category:Thermometers \"Category:Thermometers\")\n\nHidden categories:\n\n- [All articles lacking reliable references](https:\/\/en.wikipedia.org\/wiki\/Category:All_articles_lacking_reliable_references \"Category:All articles lacking reliable references\")\n- [Articles lacking reliable references from November 2017](https:\/\/en.wikipedia.org\/wiki\/Category:Articles_lacking_reliable_references_from_November_2017 \"Category:Articles lacking reliable references from November 2017\")\n- [CS1 maint: work 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Wikipedia® is a registered trademark of the [Wikimedia Foundation, Inc.](https:\/\/wikimediafoundation.org\/), a non-profit organization.\n\n- [Privacy policy](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Policy:Privacy_policy)\n- [About Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:About)\n- [Disclaimers](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:General_disclaimer)\n- [Contact Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contact_us)\n- [Legal & safety contacts](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Legal:Wikimedia_Foundation_Legal_and_Safety_Contact_Information)\n- [Code of Conduct](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Policy:Universal_Code_of_Conduct)\n- [Developers](https:\/\/developer.wikimedia.org\/)\n- [Statistics](https:\/\/stats.wikimedia.org\/#\/en.wikipedia.org)\n- [Cookie statement](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Policy:Cookie_statement)\n- [Mobile view](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&mobileaction=toggle_view_mobile)\n\n- [![Wikimedia Foundation](https:\/\/en.wikipedia.org\/static\/images\/footer\/wikimedia.svg)](https:\/\/www.wikimedia.org\/)\n- [![Powered by MediaWiki](https:\/\/en.wikipedia.org\/w\/resources\/assets\/mediawiki_compact.svg)](https:\/\/www.mediawiki.org\/)\n\nSearch\n\nToggle the table of contents\n\nHuman body temperature\n\n16 languages\n\n[Add topic](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature)","attrs_readable_markdown":"**Normal human body temperature** (**normothermia**, **euthermia**) is the typical [temperature](https:\/\/en.wikipedia.org\/wiki\/Temperature \"Temperature\") range found in [humans](https:\/\/en.wikipedia.org\/wiki\/Humans \"Humans\"). The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F).[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kar2008-8)[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-pmid_37669046-9)\n\nHuman body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the [body](https:\/\/en.wikipedia.org\/wiki\/Human_body \"Human body\") the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a [homeostatic](https:\/\/en.wikipedia.org\/wiki\/Homeostasis \"Homeostasis\") function known as [thermoregulation](https:\/\/en.wikipedia.org\/wiki\/Thermoregulation_in_humans \"Thermoregulation in humans\"), in which adjustment of temperature is triggered by the [central nervous system](https:\/\/en.wikipedia.org\/wiki\/Central_nervous_system \"Central nervous system\").\n\n## Methods of measurement\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=1 \"Edit section: Methods of measurement\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/9\/93\/Clinical_thermometer_38.7.JPG\/250px-Clinical_thermometer_38.7.JPG)](https:\/\/en.wikipedia.org\/wiki\/File:Clinical_thermometer_38.7.JPG)\n\nA [medical thermometer](https:\/\/en.wikipedia.org\/wiki\/Medical_thermometer \"Medical thermometer\") showing a temperature reading of 38.7 °C (101.7 °F)\n\nTaking a human's temperature is an initial part of a full [clinical examination](https:\/\/en.wikipedia.org\/wiki\/Clinical_examination \"Clinical examination\"). There are various types of [medical thermometers](https:\/\/en.wikipedia.org\/wiki\/Medical_thermometer \"Medical thermometer\"), as well as sites used for measurement, including:\n\n- Under the armpit (axillary temperature)\n- In the mouth (oral temperature)\n- In the [rectum](https:\/\/en.wikipedia.org\/wiki\/Rectum \"Rectum\") (rectal temperature)\n- In the ear (tympanic temperature)\n- On the skin of the forehead over the [temporal artery](https:\/\/en.wikipedia.org\/wiki\/Superficial_temporal_artery \"Superficial temporal artery\")\n- Using [heat flux sensors](https:\/\/en.wikipedia.org\/wiki\/Heat_flux_sensor \"Heat flux sensor\")\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/2\/21\/Body_Temp_Variation.svg\/330px-Body_Temp_Variation.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:Body_Temp_Variation.svg)\n\nDiurnal variation in body temperature, ranging from about 37.5 °C (99.5 °F) from 10 a.m. to 6 p.m., and falling to about 36.4 °C (97.5 °F) from 2 a.m. to 6 a.m. (Based on figure in entry for 'Animal Heat' in 11th edition of the [Encyclopædia Britannica](https:\/\/en.wikipedia.org\/wiki\/Encyclop%C3%A6dia_Britannica \"Encyclopædia Britannica\"), 1910)\n\n[Temperature control](https:\/\/en.wikipedia.org\/wiki\/Thermoregulation_in_humans \"Thermoregulation in humans\") ([thermoregulation](https:\/\/en.wikipedia.org\/wiki\/Thermoregulation \"Thermoregulation\")) is a [homeostatic](https:\/\/en.wikipedia.org\/wiki\/Homeostatic \"Homeostatic\") mechanism that keeps the organism at optimum [operating temperature](https:\/\/en.wikipedia.org\/wiki\/Operating_temperature \"Operating temperature\"), as the temperature affects the rate of [chemical reactions](https:\/\/en.wikipedia.org\/wiki\/Chemical_reaction \"Chemical reaction\"). In [humans](https:\/\/en.wikipedia.org\/wiki\/Human \"Human\"), the average internal temperature is widely accepted to be 37 °C (98.6 °F), a \"normal\" temperature established in the 1800s. But newer studies show that average internal temperature for men and women is 36.4 °C (97.5 °F).[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-10) No person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's [circadian rhythm](https:\/\/en.wikipedia.org\/wiki\/Circadian_rhythm \"Circadian rhythm\"). The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors.[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly-11)\n\nIn addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.90 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day.\n\nNormal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F).[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Mac-12) This means that any oral temperature between 36.3 and 37.3 °C (97.3 and 99.1 °F) is likely to be normal.[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-13)\n\nThe normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F).[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kar2008-8)[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-pmid_37669046-9) In adults a review of the literature has found a wider range of 33.2–38.2 °C (91.8–100.8 °F) for normal temperatures, depending on the gender and location measured.[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-SundLevander2002-14)\n\nReported values vary depending on how it is measured: oral (under the tongue): 36.8 ± 0.4 °C (98.2 ± 0.7 °F),[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) internal ([rectal](https:\/\/en.wikipedia.org\/wiki\/Rectal \"Rectal\"), [vaginal](https:\/\/en.wikipedia.org\/wiki\/Vagina \"Vagina\")): 37.0 °C (98.6 °F).[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) A rectal or vaginal measurement taken directly inside the body cavity is typically slightly higher than oral measurement, and oral measurement is somewhat higher than skin measurement. Other places, such as under the arm or in the ear, produce different typical temperatures.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) While some people think of these averages as representing normal or ideal measurements, a wide range of temperatures has been found in healthy people.[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-CC09-5) The body temperature of a healthy person varies during the day by about 0.5 °C (0.9 °F) with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) Other circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the [nadir](https:\/\/en.wikipedia.org\/wiki\/Nadir#Medicine \"Nadir\"), is one of the primary markers for [circadian rhythms](https:\/\/en.wikipedia.org\/wiki\/Circadian_rhythm \"Circadian rhythm\"). The body temperature also changes when a person is hungry, sleepy, sick, or cold.\n\nBody temperature normally fluctuates over the day following [circadian rhythms](https:\/\/en.wikipedia.org\/wiki\/Circadian_rhythm \"Circadian rhythm\"), with the lowest levels around 4 a.m. and the highest in the late afternoon, between 4:00 and 6:00 p.m. (assuming the person sleeps at night and stays awake during the day).[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Mac-12)[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) Therefore, an oral temperature of 37.3 °C (99.1 °F) would, strictly speaking, be a normal, healthy temperature in the afternoon but not in the early morning.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) An individual's body temperature typically changes by about 0.5 °C (0.9 °F) between its highest and lowest points each day.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15)\n\nBody temperature is sensitive to many hormones, so women have a temperature rhythm that varies with the [menstrual cycle](https:\/\/en.wikipedia.org\/wiki\/Menstrual_cycle \"Menstrual cycle\"), called a *circamensal* rhythm.[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly-11)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] A woman's [basal body temperature](https:\/\/en.wikipedia.org\/wiki\/Basal_body_temperature \"Basal body temperature\") rises sharply after [ovulation](https:\/\/en.wikipedia.org\/wiki\/Ovulation \"Ovulation\"), as [estrogen](https:\/\/en.wikipedia.org\/wiki\/Estrogen \"Estrogen\") production decreases and [progesterone](https:\/\/en.wikipedia.org\/wiki\/Progesterone \"Progesterone\") increases. [Fertility awareness](https:\/\/en.wikipedia.org\/wiki\/Fertility_awareness \"Fertility awareness\") programs use this change to identify when a woman has ovulated to achieve or avoid [pregnancy](https:\/\/en.wikipedia.org\/wiki\/Pregnancy \"Pregnancy\"). During the [luteal phase](https:\/\/en.wikipedia.org\/wiki\/Luteal_phase \"Luteal phase\") of the menstrual cycle, both the lowest and the average temperatures are slightly higher than during other parts of the cycle. However, the amount that the temperature rises during each day is slightly lower than typical, so the highest temperature of the day is not very much higher than usual.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly1-16)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] [Hormonal contraceptives](https:\/\/en.wikipedia.org\/wiki\/Hormonal_contraceptive \"Hormonal contraceptive\") both suppress the circamensal rhythm and raise the typical body temperature by about 0.6 °C (1.1 °F).[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly-11)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\]\n\nTemperature also may vary with the change of [seasons](https:\/\/en.wikipedia.org\/wiki\/Season \"Season\") during each year. This pattern is called a *circannual* rhythm.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly1-16)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] Studies of seasonal variations have produced inconsistent results. People living in different climates may have different seasonal patterns.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIt has been found that physically active individuals have larger changes in body temperature throughout the day. Physically active people have been reported to have lower body temperatures than their less active peers in the early morning and similar or higher body temperatures later in the day.[\\[17\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Atkinson-17)\n\nWith increased age, both average body temperature and the amount of daily variability in the body temperature tend to decrease.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kelly1-16)\\[*[unreliable medical source?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\] Elderly people may have a decreased ability to generate body heat during a fever, so even a [somewhat elevated temperature](https:\/\/en.wikipedia.org\/wiki\/Low-grade_fever \"Low-grade fever\") can indicate a serious underlying cause in [geriatrics](https:\/\/en.wikipedia.org\/wiki\/Geriatrics \"Geriatrics\"). One study suggested that the average body temperature has also decreased since the 1850s.[\\[18\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-18) The study's authors believe the most likely explanation for the change is a reduction in inflammation at the population level due to decreased chronic infections and improved hygiene.[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-19)\n\n### Measurement methods\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=4 \"Edit section: Measurement methods\")\\]\n\n| Method | Women | Men |\n|---|---|---|\n| Oral | 33\\.2–38.1 °C (91.8–100.6 °F) | 35\\.7–37.7 °C (96.3–99.9 °F) |\n| Rectal | 36\\.8–37.1 °C (98.2–98.8 °F) | 36\\.7–37.5 °C (98.1–99.5 °F) |\n| Tympanic | 35\\.7–37.5 °C (96.3–99.5 °F) | 35\\.5–37.5 °C (95.9–99.5 °F) |\n| Axillary | 35\\.5–37.0 °C (95.9–98.6 °F) |   |\n\nDifferent methods used for measuring temperature produce different results. The temperature reading depends on which part of the body is being measured. The typical daytime temperatures among healthy adults are as follows:\n\n- Temperature in the rectum (rectal), vagina, or in the ear (tympanic) is about 37.5 °C (99.5 °F)[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Elert2005-20)\\[*[medical citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\]\n- Temperature in the mouth (oral) is about 36.8 °C (98.2 °F)[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Mac-12)\n- Temperature under the arm (axillary) is about 36.5 °C (97.7 °F)[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Elert2005-20)\\[*[medical citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Identifying_reliable_sources_\\(medicine\\) \"Wikipedia:Identifying reliable sources (medicine)\")*\\]\n\nGenerally, oral, rectal, gut, and core body temperatures, although slightly different, are well-correlated.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nOral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open. [Mouth breathing](https:\/\/en.wikipedia.org\/wiki\/Mouth_breathing \"Mouth breathing\"), cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures.[\\[21\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-21)\n\nEach measurement method also has different normal ranges depending on sex.[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-SundLevander2002-14)\n\n### Infrared thermometer\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=5 \"Edit section: Infrared thermometer\")\\]\n\nAs of 2016, reviews of infrared thermometers have found them to be of variable accuracy.[\\[22\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-22) This includes tympanic infrared thermometers in children.[\\[23\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-23)\n\n### Variations due to outside factors\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=6 \"Edit section: Variations due to outside factors\")\\]\n\nSleep disturbances also affect temperatures. Normally, body temperature drops significantly at a person's normal bedtime and throughout the night. Short-term [sleep deprivation](https:\/\/en.wikipedia.org\/wiki\/Sleep_deprivation \"Sleep deprivation\") produces a higher temperature at night than normal, but long-term sleep deprivation appears to reduce temperatures.[\\[24\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-24) [Insomnia](https:\/\/en.wikipedia.org\/wiki\/Insomnia \"Insomnia\") and poor sleep quality are associated with smaller and later drops in body temperature.[\\[25\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-25) Similarly, waking up unusually early, sleeping in, [jet lag](https:\/\/en.wikipedia.org\/wiki\/Jet_lag \"Jet lag\") and changes to [shift work](https:\/\/en.wikipedia.org\/wiki\/Shift_work \"Shift work\") schedules may affect body temperature.\n\nA temperature *setpoint* is the level at which the body attempts to maintain its temperature. When the setpoint is raised, the result is a fever. Most fevers are caused by [infectious disease](https:\/\/en.wikipedia.org\/wiki\/Infectious_disease \"Infectious disease\") and can be lowered, if desired, with [antipyretic](https:\/\/en.wikipedia.org\/wiki\/Antipyretic \"Antipyretic\") medications.\n\nAn early morning temperature higher than 37.3 °C (99.1 °F) or a late afternoon temperature higher than 37.7 °C (99.9 °F) is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) Lower thresholds are sometimes appropriate for elderly people.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15) The normal daily temperature variation is typically 0.5 °C (0.90 °F), but can be greater among people recovering from a fever.[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Longo-15)\n\nAn organism at optimum temperature is considered *afebrile*, meaning \"[without fever](https:\/\/en.wikipedia.org\/wiki\/Apyrexy \"Apyrexy\")\".[\\[26\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-26) If temperature is raised, but the setpoint is not raised, then the result is [hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\").\n\nHyperthermia occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably. Hyperthermia at or above about 40 °C (104 °F) is a life-threatening medical emergency that requires immediate treatment. Common symptoms include headache, confusion, and fatigue. If sweating has resulted in dehydration, then the affected person may have dry, red skin.\n\nIn a medical setting, mild hyperthermia is commonly called *heat exhaustion* or *heat prostration*; severe hyperthermia is called *heat stroke*. Heatstroke may come on suddenly, but it usually follows the untreated milder stages. Treatment involves cooling and rehydrating the body; fever-reducing drugs are useless for this condition. This may be done by moving out of direct sunlight to a cooler and shaded environment, drinking water, removing clothing that might keep heat close to the body, or sitting in front of a fan. Bathing in tepid or cool water, or even just [washing the face](https:\/\/en.wikipedia.org\/wiki\/Face_washing \"Face washing\") and other exposed areas of the skin, can be helpful.\n\nWith fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers.\n\nIn hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be [deliberately induced as a medical treatment](https:\/\/en.wikipedia.org\/wiki\/Therapeutic_hypothermia \"Therapeutic hypothermia\"). Symptoms usually appear when the body's core temperature drops by 1–2 °C (1.8–3.6 °F) below normal temperature.\n\n### Basal body temperature\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=11 \"Edit section: Basal body temperature\")\\]\n\nBasal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature. In women, temperature differs at various points in the [menstrual cycle](https:\/\/en.wikipedia.org\/wiki\/Menstrual_cycle \"Menstrual cycle\"), and this can be used in the long term to track ovulation both to aid conception or avoid pregnancy. This process is called [fertility awareness](https:\/\/en.wikipedia.org\/wiki\/Fertility_awareness \"Fertility awareness\").\n\nCore temperature, also called core body temperature, is the operating temperature of an [organism](https:\/\/en.wikipedia.org\/wiki\/Organism \"Organism\"), specifically in deep structures of the body such as the [liver](https:\/\/en.wikipedia.org\/wiki\/Liver \"Liver\"), in comparison to temperatures of peripheral tissues. Core temperature is normally maintained within a narrow range so that essential enzymatic reactions can occur. Significant core temperature elevation ([hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\")) or depression ([hypothermia](https:\/\/en.wikipedia.org\/wiki\/Hypothermia \"Hypothermia\")) over more than a brief period of time is fatal.\n\nTemperature examination in the [heart](https:\/\/en.wikipedia.org\/wiki\/Heart \"Heart\"), using a catheter, is the traditional [gold standard](https:\/\/en.wikipedia.org\/wiki\/Gold_standard_\\(test\\) \"Gold standard (test)\") measurement used to estimate core temperature (oral temperature is affected by hot or cold drinks, ambient temperature fluctuations as well as mouth-breathing). Since catheters are highly invasive, the generally accepted alternative for measuring core body temperature is through rectal measurements. Rectal temperature is expected to be approximately 1 °F (0.56 °C) higher than an oral temperature taken on the same person at the same time. Ear thermometers measure temperature from the [tympanic membrane](https:\/\/en.wikipedia.org\/wiki\/Tympanic_membrane \"Tympanic membrane\") using [infrared](https:\/\/en.wikipedia.org\/wiki\/Infrared \"Infrared\") sensors and also aim to measure core body temperature, since the blood supply of this membrane is directly shared with the [brain](https:\/\/en.wikipedia.org\/wiki\/Brain \"Brain\"). However, this method of measuring body temperature is not as accurate as rectal measurement and has a low sensitivity for fever, failing to determine three or four out of every ten fever measurements in children.[\\[27\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Dodd-27) Ear temperature measurement may be acceptable for observing trends in body temperature but is less useful in consistently identifying and diagnosing fever.\n\nUntil recently, direct measurement of core body temperature required either an ingestible device or surgical insertion of a probe. Therefore, a variety of indirect methods have commonly been used as the preferred alternative to these more accurate albeit more invasive methods. The [rectal](https:\/\/en.wikipedia.org\/wiki\/Rectum \"Rectum\") or [vaginal](https:\/\/en.wikipedia.org\/wiki\/Vagina \"Vagina\") temperature is generally considered to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible [thermistors](https:\/\/en.wikipedia.org\/wiki\/Thermistor \"Thermistor\") in [capsule](https:\/\/en.wikipedia.org\/wiki\/Capsule_\\(pharmacy\\) \"Capsule (pharmacy)\") form were produced, allowing the temperature inside the [digestive tract](https:\/\/en.wikipedia.org\/wiki\/Digestive_tract \"Digestive tract\") to be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement.[\\[28\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-SciDirect-28) More recently, a new method using [heat flux sensors](https:\/\/en.wikipedia.org\/wiki\/Heat_flux_sensor \"Heat flux sensor\") have been developed. Several research papers show that its accuracy is similar to the invasive methods.[\\[29\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-29)[\\[30\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-30)[\\[31\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-31)\n\nMeasurement within the body finds internal variation temperatures as different as 21.5 °C (70.7 °F) for the [radial artery](https:\/\/en.wikipedia.org\/wiki\/Radial_artery \"Radial artery\") and 31.1 °C (88.0 °F) for the [brachial artery](https:\/\/en.wikipedia.org\/wiki\/Brachial_artery \"Brachial artery\").[\\[32\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32) It has been observed that \"chaos\" has been \"introduced into physiology by the fictitious assumption of a constant blood temperature\".[\\[32\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32)\n\n## Temperature variation\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=14 \"Edit section: Temperature variation\")\\]\n\n- 44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F).[\\[33\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-33)[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-34)\n- 43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur.\n- 42 °C (107.6 °F) – Subject may turn red. They may become comatose, be in severe delirium, and convulsions can occur.\n- 41 °C (105.8 °F) – ([Medical emergency](https:\/\/en.wikipedia.org\/wiki\/Medical_emergency \"Medical emergency\")) – Fainting, severe headache, dizziness, confusion, hallucinations, delirium, and drowsiness can occur. There may also be [palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitations \"Palpitations\") and breathlessness.\n- 40 °C (104 °F) – Fainting, dehydration, weakness, headache, breathlessness, and dizziness may occur as well as profuse sweating.\n- 39 °C (102.2 °F) – Severe sweating, and red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer convulsions at this temperature.\n- 38 °C (100.4 °F) – (Classed as [hyperthermia](https:\/\/en.wikipedia.org\/wiki\/Hyperthermia \"Hyperthermia\") if not caused by a [fever](https:\/\/en.wikipedia.org\/wiki\/Fever \"Fever\")) – Feeling hot, sweating, feeling thirsty, feeling very uncomfortable.\n- 37\\.6 °C (99.7 °F) — Classed as a slight fever. May lose appetite, feeling hot, feeling uncomfortable, feeling thirsty.\n\n- 36\\.5–37.5 °C (97.7–99.5 °F) is a typically reported range for normal body temperature.[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-Kar2008-8)\n\n- 35\\.5 °C (95.9 °F) – Feeling cold, mild to moderate shivering. This can be a normal body temperature for sleeping.\n- 35 °C (95 °F) – Threshold for [hypothermia](https:\/\/en.wikipedia.org\/wiki\/Hypothermia \"Hypothermia\"). Intense shivering, numbness and bluish\/grayness of the skin. There is the possibility of heart irritability.\n- 34 °C (93.2 °F) – Severe shivering, loss of movement of fingers, blueness, and confusion. Some behavioral changes may take place.\n- 33 °C (91.4 °F) – Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heartbeat, shallow breathing. Shivering may stop. The subject may be unresponsive to certain stimuli.\n- 32 °C (89.6 °F) – ([Medical emergency](https:\/\/en.wikipedia.org\/wiki\/Medical_emergency \"Medical emergency\")) – Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent. Reflex may be absent or very slight.\n- 31 °C (87.8 °F) – Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems.\n- 28 °C (82.4 °F) – Severe heart rhythm disturbances are likely and breathing may stop at any time. The person may appear to be dead.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n- 24–26 °C (75.2–78.8 °F) or less – Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures lower than 12.7 °C (54.9 °F).[\\[35\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-35) The lowest recorded core temperature from a patient with accidental hypothermia who survived without neurological [sequelae](https:\/\/en.wikipedia.org\/wiki\/Sequela \"Sequela\") is 11.8 °C (53.2 °F).[\\[36\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-36)\n\nThere are non-verbal corporal cues that can hint at an individual experiencing a low body temperature, which can be used for those with [dysphasia](https:\/\/en.wikipedia.org\/wiki\/Dysphasia \"Dysphasia\") or infants.[\\[37\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-37) Examples of non-[verbal](https:\/\/en.wiktionary.org\/wiki\/verbal \"wikt:verbal\") cues of [coldness](https:\/\/en.wikipedia.org\/wiki\/Coldness \"Coldness\") include stillness and being lethargic, unusual paleness of skin among light-skinned people, and, among males, shrinkage, and contraction of the [scrotum](https:\/\/en.wikipedia.org\/wiki\/Scrotum \"Scrotum\").[\\[38\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-38)\n\n## Effect of environment\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=18 \"Edit section: Effect of environment\")\\]\n\nEnvironmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The [psychrometric temperature](https:\/\/en.wikipedia.org\/wiki\/Psychrometrics \"Psychrometrics\"), of which the [wet-bulb temperature](https:\/\/en.wikipedia.org\/wiki\/Wet-bulb_temperature \"Wet-bulb temperature\") is the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value consistent with human life.\n\nA 2022 study on the effect of heat on young people found that the critical wet-bulb temperature at which heat stress can no longer be compensated, Twb,crit, in young, healthy adults performing tasks at modest metabolic rates mimicking basic activities of daily life was much lower than the 35 °C (95 °F) usually assumed, at about 30.55 °C (86.99 °F) in 36–40 °C (97–104 °F) humid environments, but progressively decreased in hotter, dry ambient environments.[\\[39\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-vecellio-39)[\\[40\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-timperley-40)\n\nAt low temperatures the body thermoregulates by generating heat, but this becomes unsustainable at extremely low temperatures.\n\n## Historical understanding\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Human_body_temperature&action=edit&section=19 \"Edit section: Historical understanding\")\\]\n\nIn the 19th century, most books quoted \"blood heat\" as 98 °F, until a study published the mean (but not the variance) of a large sample as 36.88 °C (98.38 °F).[\\[41\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-41) Subsequently, that mean was widely quoted as \"37 °C or 98.4 °F\"[\\[42\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-42)[\\[43\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-43) until editors realized 37 °C is equal to 98.6 °F, not 98.4 °F. The 37 °C value was set by German physician [Carl Reinhold August Wunderlich](https:\/\/en.wikipedia.org\/wiki\/Carl_Reinhold_August_Wunderlich \"Carl Reinhold August Wunderlich\") in his 1868 book,[\\[44\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-44) which put temperature charts into widespread clinical use.[\\[45\\]](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_note-45) Dictionaries and other sources\\[*[which?](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Avoid_weasel_words \"Wikipedia:Avoid weasel words\")*\\] that quoted these averages did add the word \"about\" to show that there is some variance, but generally did not state how wide the variance is.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n1. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Rosen_1-0)**\n   Marx J (2006). *Rosen's emergency medicine : concepts and clinical practice* (6th ed.). Philadelphia: Mosby\/Elsevier. p. 2239. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n   \n   [978-0-323-02845-5](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-323-02845-5 \"Special:BookSources\/978-0-323-02845-5\")\n   \n   . [OCLC](https:\/\/en.wikipedia.org\/wiki\/OCLC_\\(identifier\\) \"OCLC (identifier)\") [58533794](https:\/\/search.worldcat.org\/oclc\/58533794).\n2. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-pmid18788094_2-0)**\n   Hutchison JS, Ward RE, Lacroix J, Hébert PC, Barnes MA, Bohn DJ, et al. (June 2008). \"Hypothermia therapy after traumatic brain injury in children\". *The New England Journal of Medicine*. **358** (23): 2447–56\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1056\/NEJMoa0706930](https:\/\/doi.org\/10.1056%2FNEJMoa0706930). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18525042](https:\/\/pubmed.ncbi.nlm.nih.gov\/18525042).\n3. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-3)**\n   Pryor JA, Prasad AS (2008). [*Physiotherapy for Respiratory and Cardiac Problems: Adults and Paediatrics*](https:\/\/books.google.ca\/books?id=5n9fseWPLowC&pg=PA8). Elsevier Health Sciences. p. 8. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n   \n   [978-0702039744](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0702039744 \"Special:BookSources\/978-0702039744\")\n   \n   . \"Body temperature is maintained within the range 36.5-37.5 °C. It is lowest in the early morning and highest in the afternoon.\"\n4. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-NC08_4-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-NC08_4-1)\n   Axelrod YK, Diringer MN (May 2008). \"Temperature management in acute neurologic disorders\". *Neurologic Clinics*. **26** (2): 585–603, xi. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.ncl.2008.02.005](https:\/\/doi.org\/10.1016%2Fj.ncl.2008.02.005). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18514828](https:\/\/pubmed.ncbi.nlm.nih.gov\/18514828).\n5. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-CC09_5-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-CC09_5-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-CC09_5-2)\n   Laupland KB (July 2009). \"Fever in the critically ill medical patient\". *Critical Care Medicine*. **37** (7 Suppl): S273-8. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1097\/CCM.0b013e3181aa6117](https:\/\/doi.org\/10.1097%2FCCM.0b013e3181aa6117). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [19535958](https:\/\/pubmed.ncbi.nlm.nih.gov\/19535958).\n6. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-6)**\n   Grunau BE, Wiens MO, Brubacher JR (September 2010). \"Dantrolene in the treatment of MDMA-related hyperpyrexia: a systematic review\". *Cjem*. **12** (5): 435–42\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1017\/s1481803500012598](https:\/\/doi.org\/10.1017%2Fs1481803500012598). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [20880437](https:\/\/pubmed.ncbi.nlm.nih.gov\/20880437). \"Dantrolene may also be associated with improved survival and reduced complications, especially in patients with extreme (≥ 42 °C) or severe (≥ 40 °C) hyperpyrexia\"\n7. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-7)**\n   Sharma HS, ed. (2007). [*Neurobiology of Hyperthermia*](https:\/\/books.google.com\/books?id=Vk1UTlmEwrQC&pg=485#v=onepage&q=hyperpyrexia%20core%20temperature&f=false) (1st ed.). Elsevier. pp. 175–177, 485. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n   \n   [9780080549996](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/9780080549996 \"Special:BookSources\/9780080549996\")\n   \n   . Retrieved 19 November 2016. \"Despite the myriad of complications associated with heat illness, an elevation of core temperature above 41.0 °C (often referred to as fever or hyperpyrexia) is the most widely recognized symptom of this syndrome.\"\n8. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kar2008_8-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kar2008_8-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kar2008_8-2)\n   Hutchison, James S.; et al. (June 2008). [\"Hypothermia therapy after traumatic brain injury in children\"](https:\/\/doi.org\/10.1056%2FNEJMoa0706930). *New England Journal of Medicine*. **358** (23): 2447–2456\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1056\/NEJMoa0706930](https:\/\/doi.org\/10.1056%2FNEJMoa0706930). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18525042](https:\/\/pubmed.ncbi.nlm.nih.gov\/18525042). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [46833](https:\/\/api.semanticscholar.org\/CorpusID:46833). \"We hypothesized that, as compared with normothermia (36.5 to 37.5°C), treatment with hypothermia...\"\n9. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-pmid_37669046_9-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-pmid_37669046_9-1)\n   Ley, C; Heath, F; Hastie, T; Gao, Z; Protsiv, M; Parsonnet, J (5 September 2023). [\"Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC10481327). *JAMA Internal Medicine*. **183** (10): 1128–1135\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1001\/jamainternmed.2023.4291](https:\/\/doi.org\/10.1001%2Fjamainternmed.2023.4291). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [10481327](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC10481327). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [37669046](https:\/\/pubmed.ncbi.nlm.nih.gov\/37669046).\n10. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-10)**\n    Weintraub, Karen (April 2020). [\"Are Human Body Temperatures Cooling Down?\"](https:\/\/www.scientificamerican.com\/article\/are-human-body-temperatures-cooling-down\/). *Scientific American*. Retrieved 10 March 2022.\n11. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly_11-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly_11-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly_11-2)\n    Kelly, Greg S. (March 2007). [\"Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease\"](https:\/\/web.archive.org\/web\/20170809134435\/http:\/\/altmedrev.com\/publications\/12\/1\/49.pdf) (PDF). *Alternative Medicine Review*. **12** (1): 49–62\\. [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [17397267](https:\/\/pubmed.ncbi.nlm.nih.gov\/17397267). Archived from [the original](http:\/\/www.altmedrev.com\/publications\/12\/1\/49.pdf) (PDF) on 2017-08-09. Retrieved 2016-12-28.\n12. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Mac_12-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Mac_12-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Mac_12-2)\n    Mackowiak, Philip A.; Wasserman, Steven S.; Levine, Myron M. (1992-09-23). \"A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich\". *Journal of the American Medical Association*. **268** (12): 1578–1580\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1001\/jama.1992.03490120092034](https:\/\/doi.org\/10.1001%2Fjama.1992.03490120092034). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [1302471](https:\/\/pubmed.ncbi.nlm.nih.gov\/1302471).\n13. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-13)**\n    Del Bene, Victor E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.), [\"Temperature\"](https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK331\/), *Clinical Methods: The History, Physical, and Laboratory Examinations* (3rd ed.), Boston: Butterworths, [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n    \n    [978-0-409-90077-4](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-409-90077-4 \"Special:BookSources\/978-0-409-90077-4\")\n    \n    , [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [21250173](https:\/\/pubmed.ncbi.nlm.nih.gov\/21250173), retrieved 2023-02-15\n    \n    `{{citation}}`: CS1 maint: work parameter with ISBN ([link](https:\/\/en.wikipedia.org\/wiki\/Category:CS1_maint:_work_parameter_with_ISBN \"Category:CS1 maint: work parameter with ISBN\"))\n14. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SundLevander2002_14-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SundLevander2002_14-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SundLevander2002_14-2)\n    Sund-Levander, Märtha; Forsberg, Christina; Wahren, Lis Karen (2002). \"Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review\". *Scandinavian Journal of Caring Sciences*. **16** (2): 122–8\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1046\/j.1471-6712.2002.00069.x](https:\/\/doi.org\/10.1046%2Fj.1471-6712.2002.00069.x). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [12000664](https:\/\/pubmed.ncbi.nlm.nih.gov\/12000664).\n15. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-6) [***h***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-7) [***i***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-8) [***j***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Longo_15-9)\n    Longo, Dan L., ed. (2011). [*Harrison's principles of internal medicine*](https:\/\/web.archive.org\/web\/20120429231736\/http:\/\/www.accessmedicine.com\/resourceTOC.aspx?resourceID=4) (18th ed.). New York: McGraw-Hill. p. 142. [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\\(identifier\\) \"ISBN (identifier)\")\n    \n    [978-0-07-174889-6](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-07-174889-6 \"Special:BookSources\/978-0-07-174889-6\")\n    \n    . Archived from [the original](http:\/\/accessmedicine.com\/resourceTOC.aspx?resourceID=4) on 2012-04-29. Retrieved 2012-03-16.\n16. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly1_16-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly1_16-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Kelly1_16-2)\n    Kelly, Greg S. (December 2006). [\"Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging\"](https:\/\/web.archive.org\/web\/20170808231722\/http:\/\/altmedrev.com\/publications\/11\/4\/278.pdf) (PDF). *Alternative Medicine Review*. **11** (4): 278–93\\. [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [17176167](https:\/\/pubmed.ncbi.nlm.nih.gov\/17176167). Archived from [the original](http:\/\/www.altmedrev.com\/publications\/11\/4\/278.pdf) (PDF) on 2017-08-08. Retrieved 2016-12-28.\n17. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Atkinson_17-0)**\n    Atkinson, G.; Coldwells, A.; Reilly, T.; Waterhouse, J. (January 1993). \"A comparison of circadian rhythms in work performance between physically active and inactive subjects\". *Ergonomics*. **36** (1–3\\): 273–281\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1080\/00140139308967882](https:\/\/doi.org\/10.1080%2F00140139308967882). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [8440222](https:\/\/pubmed.ncbi.nlm.nih.gov\/8440222).\n18. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-18)**\n    Katz, Brigit (16 January 2020). [\"Human Body Temperature Is Getting Cooler, Study Finds\"](https:\/\/www.smithsonianmag.com\/smart-news\/human-body-temperature-getting-cooler-study-finds-180974006\/). *[Smithsonian](https:\/\/en.wikipedia.org\/wiki\/Smithsonian_\\(magazine\\) \"Smithsonian (magazine)\")*. Retrieved 22 January 2020.\n19. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-19)**\n    Protsiv, Myroslava; Ley, Catherine; Lankester, Joanna; Hastie, Trevor; [Parsonnet, Julie](https:\/\/en.wikipedia.org\/wiki\/Julie_Parsonnet \"Julie Parsonnet\") (2020-01-07). Jit, Mark; Franco, Eduardo; Waalen, Jill; Rühli, Frank (eds.). [\"Decreasing human body temperature in the United States since the Industrial Revolution\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6946399). *eLife*. **9** e49555. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.7554\/eLife.49555](https:\/\/doi.org\/10.7554%2FeLife.49555). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [2050-084X](https:\/\/search.worldcat.org\/issn\/2050-084X). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [6946399](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6946399). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [31908267](https:\/\/pubmed.ncbi.nlm.nih.gov\/31908267).\n20. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Elert2005_20-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Elert2005_20-1)\n    Wong, Lena (1997). Elert, Glenn (ed.). [\"Temperature of a healthy human (body temperature)\"](https:\/\/hypertextbook.com\/facts\/1997\/LenaWong.shtml). *The Physics Factbook*. Retrieved 2022-01-25.\n21. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-21)**\n    Newman, B. H.; Martin, C. A. (October 2001). [\"The effect of hot beverages, cold beverages, and chewing gum on oral temperature\"](https:\/\/doi.org\/10.1046%2Fj.1537-2995.2001.41101241.x). *Transfusion*. **41** (10): 1241–1243\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1046\/j.1537-2995.2001.41101241.x](https:\/\/doi.org\/10.1046%2Fj.1537-2995.2001.41101241.x). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [0041-1132](https:\/\/search.worldcat.org\/issn\/0041-1132). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [11606822](https:\/\/pubmed.ncbi.nlm.nih.gov\/11606822). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [24681501](https:\/\/api.semanticscholar.org\/CorpusID:24681501).\n22. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-22)**\n    Kiekkas, P; Stefanopoulos, N; Bakalis, N; Kefaliakos, A; Karanikolas, M (April 2016). \"Agreement of infrared temporal artery thermometry with other thermometry methods in adults: systematic review\". *Journal of Clinical Nursing*. **25** (7–8\\): 894–905\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1111\/jocn.13117](https:\/\/doi.org\/10.1111%2Fjocn.13117). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [26994990](https:\/\/pubmed.ncbi.nlm.nih.gov\/26994990).\n23. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-23)**\n    Zhen, C; Xia, Z; Long, L; Pu, Y (October 2014). \"Accuracy of infrared ear thermometry in children: a meta-analysis and systematic review\". *Clinical Pediatrics*. **53** (12): 1158–65\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1177\/0009922814536774](https:\/\/doi.org\/10.1177%2F0009922814536774). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [24879119](https:\/\/pubmed.ncbi.nlm.nih.gov\/24879119). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [24982111](https:\/\/api.semanticscholar.org\/CorpusID:24982111).\n24. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-24)**\n    Paprocki, Jonathan (2012-12-18). [\"Sleep deprivation disrupts regulation of body heat\"](https:\/\/sleepeducation.org\/sleep-deprivation-disrupts-regulation-body-heat\/). *Sleep Education*. Retrieved 2023-02-15.\n25. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-25)**\n    Lack, Leon C.; Gradisar, Michael; Van Someren, Eus J. W.; Wright, Helen R.; Lushington, Kurt (August 2008). \"The relationship between insomnia and body temperatures\". *Sleep Medicine Reviews*. **12** (4): 307–317\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.smrv.2008.02.003](https:\/\/doi.org\/10.1016%2Fj.smrv.2008.02.003). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [1087-0792](https:\/\/search.worldcat.org\/issn\/1087-0792). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18603220](https:\/\/pubmed.ncbi.nlm.nih.gov\/18603220).\n26. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-26)**\n    [\"Define Afebrile\"](https:\/\/www.dictionary.com\/browse\/afebrile).\n27. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Dodd_27-0)**\n    Dodd, Susanna R.; Lancaster, Gillian A.; Craig, Jean V.; Smyth, Rosalind L.; Williamson, Paula R. (April 2006). \"In a systematic review, infrared ear thermometry for fever diagnosis in children finds poor sensitivity\". *Journal of Clinical Epidemiology*. **59** (4): 354–7\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.jclinepi.2005.10.004](https:\/\/doi.org\/10.1016%2Fj.jclinepi.2005.10.004). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [16549256](https:\/\/pubmed.ncbi.nlm.nih.gov\/16549256).\n28. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-SciDirect_28-0)**\n    McKenzie, Jack E.; Osgood, David W. (2004). \"Validation of a new telemetric core temperature monitor\". *Journal of Thermal Biology*. **29** (7–8\\): 605. [Bibcode](https:\/\/en.wikipedia.org\/wiki\/Bibcode_\\(identifier\\) \"Bibcode (identifier)\"):[2004JTBio..29..605M](https:\/\/ui.adsabs.harvard.edu\/abs\/2004JTBio..29..605M). [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.jtherbio.2004.08.020](https:\/\/doi.org\/10.1016%2Fj.jtherbio.2004.08.020).\n29. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-29)**\n    Nidermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel (January 2014). [\"Prediction of Human Core Body Temperature Using Non-Invasive Measurement Methods\"](https:\/\/www.dora.lib4ri.ch\/empa\/islandora\/object\/empa%3A6081). *International Journal of Biometeorology*. **58** (1): 7–15\\. [Bibcode](https:\/\/en.wikipedia.org\/wiki\/Bibcode_\\(identifier\\) \"Bibcode (identifier)\"):[2014IJBm...58....7N](https:\/\/ui.adsabs.harvard.edu\/abs\/2014IJBm...58....7N). [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1007\/s00484-013-0687-2](https:\/\/doi.org\/10.1007%2Fs00484-013-0687-2). [hdl](https:\/\/en.wikipedia.org\/wiki\/Hdl_\\(identifier\\) \"Hdl (identifier)\"):[20\\.500.11850\/80468](https:\/\/hdl.handle.net\/20.500.11850%2F80468). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [23760405](https:\/\/pubmed.ncbi.nlm.nih.gov\/23760405). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [11772946](https:\/\/api.semanticscholar.org\/CorpusID:11772946).\n30. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-30)**\n    Mendt, Stefan; Maggioni, Martina Ana; Nordine, Michael; Steinach, Mathias; Opatz, Oliver; Belavy, Daniel; Felsenberg, Dieter; Koch, Joachim; Shang, Peng; Hanns-Christian, Gunga; Stahn, Alexander (2017). \"Circadian Rhythms in Bed Rest: Monitoring Core Body Temperature via Heat-Flux Approach Is Superior to Skin Surface Temperature\". *Chronobiology International*. **34** (5): 666–676\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1080\/07420528.2016.1224241](https:\/\/doi.org\/10.1080%2F07420528.2016.1224241). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [27726448](https:\/\/pubmed.ncbi.nlm.nih.gov\/27726448). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [205581198](https:\/\/api.semanticscholar.org\/CorpusID:205581198).\n31. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-31)**\n    Uth, Marc-Florian; Koch, Jochim; Sattler, Frank (2016). [\"Body Core Temperature Sensing: Challenges and New Sensor Technologies\"](https:\/\/doi.org\/10.1016%2Fj.proeng.2016.11.154). *Procedia Engineering*. **168**: 89–92\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.proeng.2016.11.154](https:\/\/doi.org\/10.1016%2Fj.proeng.2016.11.154).\n32. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-1)\n    Bazett, H. C.; Love, L.; Newton, M.; Eisenberg, L.; Day, R.; Forster, R. (1948). \"Temperature Changes in Blood Flowing in Arteries and Veins in Man\". *Journal of Applied Physiology*. **1** (1): 3–19\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1152\/jappl.1948.1.1.3](https:\/\/doi.org\/10.1152%2Fjappl.1948.1.1.3). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [8750-7587](https:\/\/search.worldcat.org\/issn\/8750-7587). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [18887571](https:\/\/pubmed.ncbi.nlm.nih.gov\/18887571).\n33. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-33)** Chudler, Eric H. [\"Biological Rhythms\"](http:\/\/faculty.washington.edu\/chudler\/clock.html), *Neuroscience for Kids*, faculty.washington.edu\n34. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-34)** [temperature registered more than 115.7\"](https:\/\/news.google.com\/newspapers?id=y4IwAAAAIBAJ&sjid=t0QDAAAAIBAJ&pg=4281,2822445&dq=115.7+degrees&hl=en), *Bulletin Journal*, August 7, 1980\n35. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-35)**\n    [\"2-latek z Polski rekordzistą. Przeżył wychłodzenie poniżej 12 st. C.\"](https:\/\/dzienniknaukowy.pl\/zdrowie\/2-latek-z-polski-rekordzista-przezyl-wychlodzenie-ponizej-12-st-c) *Dziennik Naukowy* (in Polish). 5 December 2014. Retrieved 23 September 2022.\n36. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-36)**\n    Mroczek, T.; Gladki, M.; Skalski, J. (26 June 2020). [\"Successful resuscitation from accidental hypothermia of 11.8°C: where is the lower bound for human beings?\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC7886275). *European Journal of Cardio-Thoracic Surgery*. **58** (5): 1091–1092\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1093\/ejcts\/ezaa159](https:\/\/doi.org\/10.1093%2Fejcts%2Fezaa159). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [7886275](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC7886275). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [33084865](https:\/\/pubmed.ncbi.nlm.nih.gov\/33084865).\n37. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-37)** Tomita, K., et al. \"Examination of factors affecting the intraoral perception of object size: A preliminary study.\" Journal of oral rehabilitation 44.4 (2017): 237–243.\n38. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-38)** Al-Tubaikh, Jarrah Ali. \"Infectious Diseases and Tropical Medicine.\" Internal Medicine. Springer, Cham, 2017. 441–493.\n39. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-vecellio_39-0)**\n    Vecellio, Daniel J.; Wolf, S. Tony; Cottle, Rachel M.; Kenney, W. Larry (2022-02-01). [\"Evaluating the 35°C wet-bulb temperature adaptability threshold for young, healthy subjects (PSU HEAT Project)\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC8799385). *Journal of Applied Physiology*. **132** (2): 340–345\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1152\/japplphysiol.00738.2021](https:\/\/doi.org\/10.1152%2Fjapplphysiol.00738.2021). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [8750-7587](https:\/\/search.worldcat.org\/issn\/8750-7587). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [8799385](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC8799385). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [34913738](https:\/\/pubmed.ncbi.nlm.nih.gov\/34913738).\n40. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-timperley_40-0)**\n    Timperley, Jocelyn (31 July 2022). [\"Why you need to worry about the 'wet-bulb temperature'\"](https:\/\/www.theguardian.com\/science\/2022\/jul\/31\/why-you-need-to-worry-about-the-wet-bulb-temperature). *The Guardian*.\n41. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-41)** [Inwit Publishing, Inc. and Inwit, LLC – Writings, Links and Software Demonstrations – A Fahrenheit–Celsius Activity](https:\/\/web.archive.org\/web\/20110713052807\/http:\/\/www.inwit.com\/inwit\/writings\/fahrenheitcelsiusactivity.html), inwit.com\n42. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-42)** *[Oxford Dictionary of English](https:\/\/en.wikipedia.org\/wiki\/Oxford_Dictionary_of_English \"Oxford Dictionary of English\")*, 2010 edition, entry on \"blood heat\"\n43. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-43)** *[Collins English Dictionary](https:\/\/en.wikipedia.org\/wiki\/Collins_English_Dictionary \"Collins English Dictionary\")*, 1979 edition, entry on [\"blood heat\"](https:\/\/www.collinsdictionary.com\/us\/dictionary\/english\/blood-heat)\n44. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-44)**\n    Wunderlich, Carl Reinhold August (1868). [*Das Verhalten der Eigenwärme in Krankheiten*](https:\/\/archive.org\/details\/dasverhaltender00wundgoog) \\[*The behavior of the self-warmth in diseases*\\]. Leipzig: O. Wigand.\n    \n    ; its 1871 2nd edition translated into English and published with the title [*On the temperature in diseases: a manual of medical thermometry*](https:\/\/archive.org\/details\/ontemperaturein01wundgoog).\n45. **[^](https:\/\/en.wikipedia.org\/wiki\/Human_body_temperature#cite_ref-45)** Fischetti, Mark (2018), \"Graphic Science: Goodbye, 98.6\", *Scientific American*, vol. 319, no. 6 (December)","meta_canonical":null}

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Boilerpipe Text	Normal human body temperature ( normothermia , euthermia ) is the typical temperature range found in humans . The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F). [ 8 ] [ 9 ] Human body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the body the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a homeostatic function known as thermoregulation , in which adjustment of temperature is triggered by the central nervous system . Methods of measurement [ edit ] A medical thermometer showing a temperature reading of 38.7 °C (101.7 °F) Taking a human's temperature is an initial part of a full clinical examination . There are various types of medical thermometers , as well as sites used for measurement, including: Under the armpit (axillary temperature) In the mouth (oral temperature) In the rectum (rectal temperature) In the ear (tympanic temperature) On the skin of the forehead over the temporal artery Using heat flux sensors Diurnal variation in body temperature, ranging from about 37.5 °C (99.5 °F) from 10 a.m. to 6 p.m., and falling to about 36.4 °C (97.5 °F) from 2 a.m. to 6 a.m. (Based on figure in entry for 'Animal Heat' in 11th edition of the Encyclopædia Britannica , 1910) Temperature control ( thermoregulation ) is a homeostatic mechanism that keeps the organism at optimum operating temperature , as the temperature affects the rate of chemical reactions . In humans , the average internal temperature is widely accepted to be 37 °C (98.6 °F), a "normal" temperature established in the 1800s. But newer studies show that average internal temperature for men and women is 36.4 °C (97.5 °F). [ 10 ] No person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's circadian rhythm . The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors. [ 11 ] In addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.90 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day. Normal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F). [ 12 ] This means that any oral temperature between 36.3 and 37.3 °C (97.3 and 99.1 °F) is likely to be normal. [ 13 ] The normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F). [ 8 ] [ 9 ] In adults a review of the literature has found a wider range of 33.2–38.2 °C (91.8–100.8 °F) for normal temperatures, depending on the gender and location measured. [ 14 ] Reported values vary depending on how it is measured: oral (under the tongue): 36.8 ± 0.4 °C (98.2 ± 0.7 °F), [ 15 ] internal ( rectal , vaginal ): 37.0 °C (98.6 °F). [ 15 ] A rectal or vaginal measurement taken directly inside the body cavity is typically slightly higher than oral measurement, and oral measurement is somewhat higher than skin measurement. Other places, such as under the arm or in the ear, produce different typical temperatures. [ 15 ] While some people think of these averages as representing normal or ideal measurements, a wide range of temperatures has been found in healthy people. [ 5 ] The body temperature of a healthy person varies during the day by about 0.5 °C (0.9 °F) with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change. [ 15 ] Other circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the nadir , is one of the primary markers for circadian rhythms . The body temperature also changes when a person is hungry, sleepy, sick, or cold. Body temperature normally fluctuates over the day following circadian rhythms , with the lowest levels around 4 a.m. and the highest in the late afternoon, between 4:00 and 6:00 p.m. (assuming the person sleeps at night and stays awake during the day). [ 12 ] [ 15 ] Therefore, an oral temperature of 37.3 °C (99.1 °F) would, strictly speaking, be a normal, healthy temperature in the afternoon but not in the early morning. [ 15 ] An individual's body temperature typically changes by about 0.5 °C (0.9 °F) between its highest and lowest points each day. [ 15 ] Body temperature is sensitive to many hormones, so women have a temperature rhythm that varies with the menstrual cycle , called a circamensal rhythm. [ 11 ] [ unreliable medical source? ] A woman's basal body temperature rises sharply after ovulation , as estrogen production decreases and progesterone increases. Fertility awareness programs use this change to identify when a woman has ovulated to achieve or avoid pregnancy . During the luteal phase of the menstrual cycle, both the lowest and the average temperatures are slightly higher than during other parts of the cycle. However, the amount that the temperature rises during each day is slightly lower than typical, so the highest temperature of the day is not very much higher than usual. [ 16 ] [ unreliable medical source? ] Hormonal contraceptives both suppress the circamensal rhythm and raise the typical body temperature by about 0.6 °C (1.1 °F). [ 11 ] [ unreliable medical source? ] Temperature also may vary with the change of seasons during each year. This pattern is called a circannual rhythm. [ 16 ] [ unreliable medical source? ] Studies of seasonal variations have produced inconsistent results. People living in different climates may have different seasonal patterns. [ citation needed ] It has been found that physically active individuals have larger changes in body temperature throughout the day. Physically active people have been reported to have lower body temperatures than their less active peers in the early morning and similar or higher body temperatures later in the day. [ 17 ] With increased age, both average body temperature and the amount of daily variability in the body temperature tend to decrease. [ 16 ] [ unreliable medical source? ] Elderly people may have a decreased ability to generate body heat during a fever, so even a somewhat elevated temperature can indicate a serious underlying cause in geriatrics . One study suggested that the average body temperature has also decreased since the 1850s. [ 18 ] The study's authors believe the most likely explanation for the change is a reduction in inflammation at the population level due to decreased chronic infections and improved hygiene. [ 19 ] Measurement methods [ edit ] Temperature by measurement technique [ 14 ] Method Women Men Oral 33.2–38.1 °C (91.8–100.6 °F) 35.7–37.7 °C (96.3–99.9 °F) Rectal 36.8–37.1 °C (98.2–98.8 °F) 36.7–37.5 °C (98.1–99.5 °F) Tympanic 35.7–37.5 °C (96.3–99.5 °F) 35.5–37.5 °C (95.9–99.5 °F) Axillary 35.5–37.0 °C (95.9–98.6 °F) Different methods used for measuring temperature produce different results. The temperature reading depends on which part of the body is being measured. The typical daytime temperatures among healthy adults are as follows: Temperature in the rectum (rectal), vagina, or in the ear (tympanic) is about 37.5 °C (99.5 °F) [ 20 ] [ medical citation needed ] Temperature in the mouth (oral) is about 36.8 °C (98.2 °F) [ 12 ] Temperature under the arm (axillary) is about 36.5 °C (97.7 °F) [ 20 ] [ medical citation needed ] Generally, oral, rectal, gut, and core body temperatures, although slightly different, are well-correlated. [ citation needed ] Oral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open. Mouth breathing , cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures. [ 21 ] Each measurement method also has different normal ranges depending on sex. [ 14 ] Infrared thermometer [ edit ] As of 2016, reviews of infrared thermometers have found them to be of variable accuracy. [ 22 ] This includes tympanic infrared thermometers in children. [ 23 ] Variations due to outside factors [ edit ] Sleep disturbances also affect temperatures. Normally, body temperature drops significantly at a person's normal bedtime and throughout the night. Short-term sleep deprivation produces a higher temperature at night than normal, but long-term sleep deprivation appears to reduce temperatures. [ 24 ] Insomnia and poor sleep quality are associated with smaller and later drops in body temperature. [ 25 ] Similarly, waking up unusually early, sleeping in, jet lag and changes to shift work schedules may affect body temperature. A temperature setpoint is the level at which the body attempts to maintain its temperature. When the setpoint is raised, the result is a fever. Most fevers are caused by infectious disease and can be lowered, if desired, with antipyretic medications. An early morning temperature higher than 37.3 °C (99.1 °F) or a late afternoon temperature higher than 37.7 °C (99.9 °F) is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint. [ 15 ] Lower thresholds are sometimes appropriate for elderly people. [ 15 ] The normal daily temperature variation is typically 0.5 °C (0.90 °F), but can be greater among people recovering from a fever. [ 15 ] An organism at optimum temperature is considered afebrile , meaning " without fever ". [ 26 ] If temperature is raised, but the setpoint is not raised, then the result is hyperthermia . Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably. Hyperthermia at or above about 40 °C (104 °F) is a life-threatening medical emergency that requires immediate treatment. Common symptoms include headache, confusion, and fatigue. If sweating has resulted in dehydration, then the affected person may have dry, red skin. In a medical setting, mild hyperthermia is commonly called heat exhaustion or heat prostration ; severe hyperthermia is called heat stroke . Heatstroke may come on suddenly, but it usually follows the untreated milder stages. Treatment involves cooling and rehydrating the body; fever-reducing drugs are useless for this condition. This may be done by moving out of direct sunlight to a cooler and shaded environment, drinking water, removing clothing that might keep heat close to the body, or sitting in front of a fan. Bathing in tepid or cool water, or even just washing the face and other exposed areas of the skin, can be helpful. With fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers. In hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be deliberately induced as a medical treatment . Symptoms usually appear when the body's core temperature drops by 1–2 °C (1.8–3.6 °F) below normal temperature. Basal body temperature [ edit ] Basal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature. In women, temperature differs at various points in the menstrual cycle , and this can be used in the long term to track ovulation both to aid conception or avoid pregnancy. This process is called fertility awareness . Core temperature, also called core body temperature, is the operating temperature of an organism , specifically in deep structures of the body such as the liver , in comparison to temperatures of peripheral tissues. Core temperature is normally maintained within a narrow range so that essential enzymatic reactions can occur. Significant core temperature elevation ( hyperthermia ) or depression ( hypothermia ) over more than a brief period of time is fatal. Temperature examination in the heart , using a catheter, is the traditional gold standard measurement used to estimate core temperature (oral temperature is affected by hot or cold drinks, ambient temperature fluctuations as well as mouth-breathing). Since catheters are highly invasive, the generally accepted alternative for measuring core body temperature is through rectal measurements. Rectal temperature is expected to be approximately 1 °F (0.56 °C) higher than an oral temperature taken on the same person at the same time. Ear thermometers measure temperature from the tympanic membrane using infrared sensors and also aim to measure core body temperature, since the blood supply of this membrane is directly shared with the brain . However, this method of measuring body temperature is not as accurate as rectal measurement and has a low sensitivity for fever, failing to determine three or four out of every ten fever measurements in children. [ 27 ] Ear temperature measurement may be acceptable for observing trends in body temperature but is less useful in consistently identifying and diagnosing fever. Until recently, direct measurement of core body temperature required either an ingestible device or surgical insertion of a probe. Therefore, a variety of indirect methods have commonly been used as the preferred alternative to these more accurate albeit more invasive methods. The rectal or vaginal temperature is generally considered to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible thermistors in capsule form were produced, allowing the temperature inside the digestive tract to be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement. [ 28 ] More recently, a new method using heat flux sensors have been developed. Several research papers show that its accuracy is similar to the invasive methods. [ 29 ] [ 30 ] [ 31 ] Measurement within the body finds internal variation temperatures as different as 21.5 °C (70.7 °F) for the radial artery and 31.1 °C (88.0 °F) for the brachial artery . [ 32 ] It has been observed that "chaos" has been "introduced into physiology by the fictitious assumption of a constant blood temperature". [ 32 ] Temperature variation [ edit ] 44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F). [ 33 ] [ 34 ] 43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur. 42 °C (107.6 °F) – Subject may turn red. They may become comatose, be in severe delirium, and convulsions can occur. 41 °C (105.8 °F) – ( Medical emergency ) – Fainting, severe headache, dizziness, confusion, hallucinations, delirium, and drowsiness can occur. There may also be palpitations and breathlessness. 40 °C (104 °F) – Fainting, dehydration, weakness, headache, breathlessness, and dizziness may occur as well as profuse sweating. 39 °C (102.2 °F) – Severe sweating, and red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer convulsions at this temperature. 38 °C (100.4 °F) – (Classed as hyperthermia if not caused by a fever ) – Feeling hot, sweating, feeling thirsty, feeling very uncomfortable. 37.6 °C (99.7 °F) — Classed as a slight fever. May lose appetite, feeling hot, feeling uncomfortable, feeling thirsty. 36.5–37.5 °C (97.7–99.5 °F) is a typically reported range for normal body temperature. [ 8 ] 35.5 °C (95.9 °F) – Feeling cold, mild to moderate shivering. This can be a normal body temperature for sleeping. 35 °C (95 °F) – Threshold for hypothermia . Intense shivering, numbness and bluish/grayness of the skin. There is the possibility of heart irritability. 34 °C (93.2 °F) – Severe shivering, loss of movement of fingers, blueness, and confusion. Some behavioral changes may take place. 33 °C (91.4 °F) – Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heartbeat, shallow breathing. Shivering may stop. The subject may be unresponsive to certain stimuli. 32 °C (89.6 °F) – ( Medical emergency ) – Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent. Reflex may be absent or very slight. 31 °C (87.8 °F) – Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems. 28 °C (82.4 °F) – Severe heart rhythm disturbances are likely and breathing may stop at any time. The person may appear to be dead. [ citation needed ] 24–26 °C (75.2–78.8 °F) or less – Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures lower than 12.7 °C (54.9 °F). [ 35 ] The lowest recorded core temperature from a patient with accidental hypothermia who survived without neurological sequelae is 11.8 °C (53.2 °F). [ 36 ] There are non-verbal corporal cues that can hint at an individual experiencing a low body temperature, which can be used for those with dysphasia or infants. [ 37 ] Examples of non- verbal cues of coldness include stillness and being lethargic, unusual paleness of skin among light-skinned people, and, among males, shrinkage, and contraction of the scrotum . [ 38 ] Effect of environment [ edit ] Environmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The psychrometric temperature , of which the wet-bulb temperature is the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value consistent with human life. A 2022 study on the effect of heat on young people found that the critical wet-bulb temperature at which heat stress can no longer be compensated, T wb,crit , in young, healthy adults performing tasks at modest metabolic rates mimicking basic activities of daily life was much lower than the 35 °C (95 °F) usually assumed, at about 30.55 °C (86.99 °F) in 36–40 °C (97–104 °F) humid environments, but progressively decreased in hotter, dry ambient environments. [ 39 ] [ 40 ] At low temperatures the body thermoregulates by generating heat, but this becomes unsustainable at extremely low temperatures. Historical understanding [ edit ] In the 19th century, most books quoted "blood heat" as 98 °F, until a study published the mean (but not the variance) of a large sample as 36.88 °C (98.38 °F). [ 41 ] Subsequently, that mean was widely quoted as "37 °C or 98.4 °F" [ 42 ] [ 43 ] until editors realized 37 °C is equal to 98.6 °F, not 98.4 °F. The 37 °C value was set by German physician Carl Reinhold August Wunderlich in his 1868 book, [ 44 ] which put temperature charts into widespread clinical use. [ 45 ] Dictionaries and other sources [ which? ] that quoted these averages did add the word "about" to show that there is some variance, but generally did not state how wide the variance is. [ citation needed ] ^ Marx J (2006). Rosen's emergency medicine : concepts and clinical practice (6th ed.). Philadelphia: Mosby/Elsevier. p. 2239. ISBN 978-0-323-02845-5 . OCLC 58533794 . ^ Hutchison JS, Ward RE, Lacroix J, Hébert PC, Barnes MA, Bohn DJ, et al. (June 2008). "Hypothermia therapy after traumatic brain injury in children". The New England Journal of Medicine . 358 (23): 2447– 56. doi : 10.1056/NEJMoa0706930 . PMID 18525042 . ^ Pryor JA, Prasad AS (2008). Physiotherapy for Respiratory and Cardiac Problems: Adults and Paediatrics . Elsevier Health Sciences. p. 8. ISBN 978-0702039744 . Body temperature is maintained within the range 36.5-37.5 °C. It is lowest in the early morning and highest in the afternoon. ^ a b Axelrod YK, Diringer MN (May 2008). "Temperature management in acute neurologic disorders". Neurologic Clinics . 26 (2): 585– 603, xi. doi : 10.1016/j.ncl.2008.02.005 . PMID 18514828 . ^ a b c Laupland KB (July 2009). "Fever in the critically ill medical patient". Critical Care Medicine . 37 (7 Suppl): S273-8. doi : 10.1097/CCM.0b013e3181aa6117 . PMID 19535958 . ^ Grunau BE, Wiens MO, Brubacher JR (September 2010). "Dantrolene in the treatment of MDMA-related hyperpyrexia: a systematic review". Cjem . 12 (5): 435– 42. doi : 10.1017/s1481803500012598 . PMID 20880437 . Dantrolene may also be associated with improved survival and reduced complications, especially in patients with extreme (≥ 42 °C) or severe (≥ 40 °C) hyperpyrexia ^ Sharma HS, ed. (2007). Neurobiology of Hyperthermia (1st ed.). Elsevier. pp. 175– 177, 485. ISBN 9780080549996 . Retrieved 19 November 2016 . Despite the myriad of complications associated with heat illness, an elevation of core temperature above 41.0 °C (often referred to as fever or hyperpyrexia) is the most widely recognized symptom of this syndrome. ^ a b c Hutchison, James S.; et al. (June 2008). "Hypothermia therapy after traumatic brain injury in children" . New England Journal of Medicine . 358 (23): 2447– 2456. doi : 10.1056/NEJMoa0706930 . PMID 18525042 . S2CID 46833 . We hypothesized that, as compared with normothermia (36.5 to 37.5°C), treatment with hypothermia... ^ a b Ley, C; Heath, F; Hastie, T; Gao, Z; Protsiv, M; Parsonnet, J (5 September 2023). "Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm" . JAMA Internal Medicine . 183 (10): 1128– 1135. doi : 10.1001/jamainternmed.2023.4291 . PMC 10481327 . PMID 37669046 . ^ Weintraub, Karen (April 2020). "Are Human Body Temperatures Cooling Down?" . Scientific American . Retrieved 10 March 2022 . ^ a b c Kelly, Greg S. (March 2007). "Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease" (PDF) . Alternative Medicine Review . 12 (1): 49– 62. PMID 17397267 . Archived from the original (PDF) on 2017-08-09 . Retrieved 2016-12-28 . ^ a b c Mackowiak, Philip A.; Wasserman, Steven S.; Levine, Myron M. (1992-09-23). "A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich". Journal of the American Medical Association . 268 (12): 1578– 1580. doi : 10.1001/jama.1992.03490120092034 . PMID 1302471 . ^ Del Bene, Victor E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.), "Temperature" , Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.), Boston: Butterworths, ISBN 978-0-409-90077-4 , PMID 21250173 , retrieved 2023-02-15 {{ citation }} : CS1 maint: work parameter with ISBN ( link ) ^ a b c Sund-Levander, Märtha; Forsberg, Christina; Wahren, Lis Karen (2002). "Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review". Scandinavian Journal of Caring Sciences . 16 (2): 122– 8. doi : 10.1046/j.1471-6712.2002.00069.x . PMID 12000664 . ^ a b c d e f g h i j Longo, Dan L., ed. (2011). Harrison's principles of internal medicine (18th ed.). New York: McGraw-Hill. p. 142. ISBN 978-0-07-174889-6 . Archived from the original on 2012-04-29 . Retrieved 2012-03-16 . ^ a b c Kelly, Greg S. (December 2006). "Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging" (PDF) . Alternative Medicine Review . 11 (4): 278– 93. PMID 17176167 . Archived from the original (PDF) on 2017-08-08 . Retrieved 2016-12-28 . ^ Atkinson, G.; Coldwells, A.; Reilly, T.; Waterhouse, J. (January 1993). "A comparison of circadian rhythms in work performance between physically active and inactive subjects". Ergonomics . 36 ( 1– 3): 273– 281. doi : 10.1080/00140139308967882 . PMID 8440222 . ^ Katz, Brigit (16 January 2020). "Human Body Temperature Is Getting Cooler, Study Finds" . Smithsonian . Retrieved 22 January 2020 . ^ Protsiv, Myroslava; Ley, Catherine; Lankester, Joanna; Hastie, Trevor; Parsonnet, Julie (2020-01-07). Jit, Mark; Franco, Eduardo; Waalen, Jill; Rühli, Frank (eds.). "Decreasing human body temperature in the United States since the Industrial Revolution" . eLife . 9 e49555. doi : 10.7554/eLife.49555 . ISSN 2050-084X . PMC 6946399 . PMID 31908267 . ^ a b Wong, Lena (1997). Elert, Glenn (ed.). "Temperature of a healthy human (body temperature)" . The Physics Factbook . Retrieved 2022-01-25 . ^ Newman, B. H.; Martin, C. A. (October 2001). "The effect of hot beverages, cold beverages, and chewing gum on oral temperature" . Transfusion . 41 (10): 1241– 1243. doi : 10.1046/j.1537-2995.2001.41101241.x . ISSN 0041-1132 . PMID 11606822 . S2CID 24681501 . ^ Kiekkas, P; Stefanopoulos, N; Bakalis, N; Kefaliakos, A; Karanikolas, M (April 2016). "Agreement of infrared temporal artery thermometry with other thermometry methods in adults: systematic review". Journal of Clinical Nursing . 25 ( 7– 8): 894– 905. doi : 10.1111/jocn.13117 . PMID 26994990 . ^ Zhen, C; Xia, Z; Long, L; Pu, Y (October 2014). "Accuracy of infrared ear thermometry in children: a meta-analysis and systematic review". Clinical Pediatrics . 53 (12): 1158– 65. doi : 10.1177/0009922814536774 . PMID 24879119 . S2CID 24982111 . ^ Paprocki, Jonathan (2012-12-18). "Sleep deprivation disrupts regulation of body heat" . Sleep Education . Retrieved 2023-02-15 . ^ Lack, Leon C.; Gradisar, Michael; Van Someren, Eus J. W.; Wright, Helen R.; Lushington, Kurt (August 2008). "The relationship between insomnia and body temperatures". Sleep Medicine Reviews . 12 (4): 307– 317. doi : 10.1016/j.smrv.2008.02.003 . ISSN 1087-0792 . PMID 18603220 . ^ "Define Afebrile" . ^ Dodd, Susanna R.; Lancaster, Gillian A.; Craig, Jean V.; Smyth, Rosalind L.; Williamson, Paula R. (April 2006). "In a systematic review, infrared ear thermometry for fever diagnosis in children finds poor sensitivity". Journal of Clinical Epidemiology . 59 (4): 354– 7. doi : 10.1016/j.jclinepi.2005.10.004 . PMID 16549256 . ^ McKenzie, Jack E.; Osgood, David W. (2004). "Validation of a new telemetric core temperature monitor". Journal of Thermal Biology . 29 ( 7– 8): 605. Bibcode : 2004JTBio..29..605M . doi : 10.1016/j.jtherbio.2004.08.020 . ^ Nidermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel (January 2014). "Prediction of Human Core Body Temperature Using Non-Invasive Measurement Methods" . International Journal of Biometeorology . 58 (1): 7– 15. Bibcode : 2014IJBm...58....7N . doi : 10.1007/s00484-013-0687-2 . hdl : 20.500.11850/80468 . PMID 23760405 . S2CID 11772946 . ^ Mendt, Stefan; Maggioni, Martina Ana; Nordine, Michael; Steinach, Mathias; Opatz, Oliver; Belavy, Daniel; Felsenberg, Dieter; Koch, Joachim; Shang, Peng; Hanns-Christian, Gunga; Stahn, Alexander (2017). "Circadian Rhythms in Bed Rest: Monitoring Core Body Temperature via Heat-Flux Approach Is Superior to Skin Surface Temperature". Chronobiology International . 34 (5): 666– 676. doi : 10.1080/07420528.2016.1224241 . PMID 27726448 . S2CID 205581198 . ^ Uth, Marc-Florian; Koch, Jochim; Sattler, Frank (2016). "Body Core Temperature Sensing: Challenges and New Sensor Technologies" . Procedia Engineering . 168 : 89– 92. doi : 10.1016/j.proeng.2016.11.154 . ^ a b Bazett, H. C.; Love, L.; Newton, M.; Eisenberg, L.; Day, R.; Forster, R. (1948). "Temperature Changes in Blood Flowing in Arteries and Veins in Man". Journal of Applied Physiology . 1 (1): 3– 19. doi : 10.1152/jappl.1948.1.1.3 . ISSN 8750-7587 . PMID 18887571 . ^ Chudler, Eric H. "Biological Rhythms" , Neuroscience for Kids , faculty.washington.edu ^ temperature registered more than 115.7" , Bulletin Journal , August 7, 1980 ^ "2-latek z Polski rekordzistą. Przeżył wychłodzenie poniżej 12 st. C." Dziennik Naukowy (in Polish). 5 December 2014 . Retrieved 23 September 2022 . ^ Mroczek, T.; Gladki, M.; Skalski, J. (26 June 2020). "Successful resuscitation from accidental hypothermia of 11.8°C: where is the lower bound for human beings?" . European Journal of Cardio-Thoracic Surgery . 58 (5): 1091– 1092. doi : 10.1093/ejcts/ezaa159 . PMC 7886275 . PMID 33084865 . ^ Tomita, K., et al. "Examination of factors affecting the intraoral perception of object size: A preliminary study." Journal of oral rehabilitation 44.4 (2017): 237–243. ^ Al-Tubaikh, Jarrah Ali. "Infectious Diseases and Tropical Medicine." Internal Medicine. Springer, Cham, 2017. 441–493. ^ Vecellio, Daniel J.; Wolf, S. Tony; Cottle, Rachel M.; Kenney, W. Larry (2022-02-01). "Evaluating the 35°C wet-bulb temperature adaptability threshold for young, healthy subjects (PSU HEAT Project)" . Journal of Applied Physiology . 132 (2): 340– 345. doi : 10.1152/japplphysiol.00738.2021 . ISSN 8750-7587 . PMC 8799385 . PMID 34913738 . ^ Timperley, Jocelyn (31 July 2022). "Why you need to worry about the 'wet-bulb temperature' " . The Guardian . ^ Inwit Publishing, Inc. and Inwit, LLC – Writings, Links and Software Demonstrations – A Fahrenheit–Celsius Activity , inwit.com ^ Oxford Dictionary of English , 2010 edition, entry on "blood heat" ^ Collins English Dictionary , 1979 edition, entry on "blood heat" ^ Wunderlich, Carl Reinhold August (1868). Das Verhalten der Eigenwärme in Krankheiten [ The behavior of the self-warmth in diseases ]. Leipzig: O. Wigand. ; its 1871 2nd edition translated into English and published with the title On the temperature in diseases: a manual of medical thermometry . ^ Fischetti, Mark (2018), "Graphic Science: Goodbye, 98.6", Scientific American , vol. 319, no. 6 (December)
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[o]") ## Contents move to sidebar hide - [(Top)](https://en.wikipedia.org/wiki/Human_body_temperature) - [1 Methods of measurement](https://en.wikipedia.org/wiki/Human_body_temperature#Methods_of_measurement) Toggle Methods of measurement subsection - [1\.1 Variations](https://en.wikipedia.org/wiki/Human_body_temperature#Variations) - [1\.2 Natural rhythms](https://en.wikipedia.org/wiki/Human_body_temperature#Natural_rhythms) - [1\.3 Measurement methods](https://en.wikipedia.org/wiki/Human_body_temperature#Measurement_methods) - [1\.4 Infrared thermometer](https://en.wikipedia.org/wiki/Human_body_temperature#Infrared_thermometer) - [1\.5 Variations due to outside factors](https://en.wikipedia.org/wiki/Human_body_temperature#Variations_due_to_outside_factors) - [2 Concept](https://en.wikipedia.org/wiki/Human_body_temperature#Concept) Toggle Concept subsection - [2\.1 Fever](https://en.wikipedia.org/wiki/Human_body_temperature#Fever) - [2\.2 Hyperthermia](https://en.wikipedia.org/wiki/Human_body_temperature#Hyperthermia) - [2\.3 Hypothermia](https://en.wikipedia.org/wiki/Human_body_temperature#Hypothermia) - [2\.4 Basal body temperature](https://en.wikipedia.org/wiki/Human_body_temperature#Basal_body_temperature) - [2\.5 Core temperature](https://en.wikipedia.org/wiki/Human_body_temperature#Core_temperature) - [2\.6 Internal variation](https://en.wikipedia.org/wiki/Human_body_temperature#Internal_variation) - [3 Temperature variation](https://en.wikipedia.org/wiki/Human_body_temperature#Temperature_variation) Toggle Temperature variation subsection - [3\.1 Hot](https://en.wikipedia.org/wiki/Human_body_temperature#Hot) - [3\.2 Normal](https://en.wikipedia.org/wiki/Human_body_temperature#Normal) - [3\.3 Cold](https://en.wikipedia.org/wiki/Human_body_temperature#Cold) - [4 Effect of environment](https://en.wikipedia.org/wiki/Human_body_temperature#Effect_of_environment) - [5 Historical understanding](https://en.wikipedia.org/wiki/Human_body_temperature#Historical_understanding) - [6 References](https://en.wikipedia.org/wiki/Human_body_temperature#References) Toggle the table of contents # Human body temperature 16 languages - [العربية](https://ar.wikipedia.org/wiki/%D8%AD%D8%B1%D8%A7%D8%B1%D8%A9_%D8%A7%D9%84%D8%AC%D8%B3%D9%85_%D8%A7%D9%84%D8%A8%D8%B4%D8%B1%D9%8A "حرارة الجسم البشري – Arabic") - [تۆرکجه](https://azb.wikipedia.org/wiki/%D8%A7%DB%8C%D9%86%D8%B3%D8%A7%D9%86%DB%8C%D9%86_%D9%86%D9%88%D8%B1%D9%85%D8%A7%D9%84_%D8%A8%D8%AF%D9%86_%D8%A7%DB%8C%D8%B3%D8%AA%DB%8C%E2%80%8C%D9%84%DB%8C%DA%AF%DB%8C "اینسانین نورمال بدن ایستی‌لیگی – South Azerbaijani") - [Català](https://ca.wikipedia.org/wiki/Temperatura_corporal_humana "Temperatura corporal humana – Catalan") - [کوردی](https://ckb.wikipedia.org/wiki/%D9%BE%D9%84%DB%95%DB%8C_%DA%AF%DB%95%D8%B1%D9%85%DB%8C%DB%8C_%D9%84%DB%95%D8%B4%DB%8C_%D9%85%D8%B1%DB%86%DA%A4 "پلەی گەرمیی لەشی مرۆڤ – Central Kurdish") - [Español](https://es.wikipedia.org/wiki/Temperatura_del_cuerpo_humano "Temperatura del cuerpo humano – Spanish") - [فارسی](https://fa.wikipedia.org/wiki/%D8%AF%D9%85%D8%A7%DB%8C_%D8%A8%D8%AF%D9%86_%D8%A7%D9%86%D8%B3%D8%A7%D9%86 "دمای بدن انسان – Persian") - [Français](https://fr.wikipedia.org/wiki/Temp%C3%A9rature_corporelle_humaine "Température corporelle humaine – French") - [עברית](https://he.wikipedia.org/wiki/%D7%98%D7%9E%D7%A4%D7%A8%D7%98%D7%95%D7%A8%D7%AA_%D7%92%D7%95%D7%A3_%D7%A0%D7%95%D7%A8%D7%9E%D7%9C%D7%99%D7%AA "טמפרטורת גוף נורמלית – Hebrew") - [Հայերեն](https://hy.wikipedia.org/wiki/%D5%84%D5%A1%D6%80%D5%A4%D5%B8%D6%82_%D5%B4%D5%A1%D6%80%D5%B4%D5%B6%D5%AB_%D5%BB%D5%A5%D6%80%D5%B4%D5%A1%D5%BD%D5%BF%D5%AB%D5%B3%D5%A1%D5%B6 "Մարդու մարմնի ջերմաստիճան – Armenian") - [Italiano](https://it.wikipedia.org/wiki/Temperatura_corporea_umana "Temperatura corporea umana – Italian") - [Bahasa Melayu](https://ms.wikipedia.org/wiki/Suhu_badan_manusia "Suhu badan manusia – Malay") - [Polski](https://pl.wikipedia.org/wiki/Temperatura_cia%C5%82a_cz%C5%82owieka "Temperatura ciała człowieka – Polish") - [ไทย](https://th.wikipedia.org/wiki/%E0%B8%AD%E0%B8%B8%E0%B8%93%E0%B8%AB%E0%B8%A0%E0%B8%B9%E0%B8%A1%E0%B8%B4%E0%B8%9B%E0%B8%81%E0%B8%95%E0%B8%B4%E0%B8%82%E0%B8%AD%E0%B8%87%E0%B8%A3%E0%B9%88%E0%B8%B2%E0%B8%87%E0%B8%81%E0%B8%B2%E0%B8%A2%E0%B8%A1%E0%B8%99%E0%B8%B8%E0%B8%A9%E0%B8%A2%E0%B9%8C "อุณหภูมิปกติของร่างกายมนุษย์ – Thai") - [Türkçe](https://tr.wikipedia.org/wiki/%C4%B0nsan_v%C3%BCcut_s%C4%B1cakl%C4%B1%C4%9F%C4%B1 "İnsan vücut sıcaklığı – Turkish") - [Tiếng Việt](https://vi.wikipedia.org/wiki/Nhi%E1%BB%87t_%C4%91%E1%BB%99_c%C6%A1_th%E1%BB%83_con_ng%C6%B0%E1%BB%9Di "Nhiệt độ cơ thể con người – Vietnamese") - [中文](https://zh.wikipedia.org/wiki/%E4%BA%BA%E9%AB%94%E6%BA%AB%E5%BA%A6 "人體溫度 – Chinese") [Edit links](https://www.wikidata.org/wiki/Special:EntityPage/Q16679262#sitelinks-wikipedia "Edit interlanguage links") - [Article](https://en.wikipedia.org/wiki/Human_body_temperature "View the content page [c]") - [Talk](https://en.wikipedia.org/wiki/Talk:Human_body_temperature "Discuss improvements to the content page [t]") English - [Read](https://en.wikipedia.org/wiki/Human_body_temperature) - [Edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit "Edit this page [e]") - [View history](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=history "Past revisions of this page [h]") Tools Tools move to sidebar hide Actions - 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[Get shortened URL](https://en.wikipedia.org/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHuman_body_temperature) Print/export - [Download as PDF](https://en.wikipedia.org/w/index.php?title=Special:DownloadAsPdf&page=Human_body_temperature&action=show-download-screen "Download this page as a PDF file") - [Printable version](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&printable=yes "Printable version of this page [p]") In other projects - [Wikimedia Commons](https://commons.wikimedia.org/wiki/Category:Human_body_temperature) - [Wikidata item](https://www.wikidata.org/wiki/Special:EntityPage/Q16679262 "Structured data on this page hosted by Wikidata [g]") Appearance move to sidebar hide From Wikipedia, the free encyclopedia Typical temperature range found in humans \| \| \| \|---\|---\| \| ![](https://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Star_of_life.svg/60px-Star_of_life.svg.png) \| This article needs more [reliable medical references](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)") for [verification](https://en.wikipedia.org/wiki/Wikipedia:Verifiability "Wikipedia:Verifiability") or relies too heavily on [primary sources](https://en.wikipedia.org/wiki/Wikipedia:Primary_sources "Wikipedia:Primary sources"). Please review the contents of the article and [add the appropriate references](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit) if you can. Unsourced or poorly sourced material may be challenged and [removed](https://en.wikipedia.org/wiki/Wikipedia:Verifiability#Burden_of_evidence "Wikipedia:Verifiability"). Find sources: ["Human body temperature"](https://www.google.com/search?as_eq=wikipedia&q=%22Human+body+temperature%22) – [news](https://www.google.com/search?tbm=nws&q=%22Human+body+temperature%22+-wikipedia&tbs=ar:1) · [newspapers](https://www.google.com/search?&q=%22Human+body+temperature%22&tbs=bkt:s&tbm=bks) · [books](https://www.google.com/search?tbs=bks:1&q=%22Human+body+temperature%22+-wikipedia) · [scholar](https://scholar.google.com/scholar?q=%22Human+body+temperature%22) · [JSTOR](https://www.jstor.org/action/doBasicSearch?Query=%22Human+body+temperature%22&acc=on&wc=on) (November 2022) \| \| \| \| \|---\|---\| \| Temperature classification \| \| \| \| \| \| \| [Core](https://en.wikipedia.org/wiki/Core_temperature#Core_temperature "Core temperature") (rectal, esophageal, etc.) \| \| [Hypothermia](https://en.wikipedia.org/wiki/Hypothermia "Hypothermia") \| \<35.0 °C (95.0 °F)[\[1\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Rosen-1) \| \| [Normal]() \| 36\.5–37.5 °C (97.7–99.5 °F)[\[2\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-pmid18788094-2)[\[3\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-3) \| \| [Fever](https://en.wikipedia.org/wiki/Fever "Fever") \| \>37.5 or 38.3 °C (99.5 or 100.9 °F)[\[4\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-NC08-4)[\[5\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-CC09-5) \| \| [Hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia") \| \>37.5 or 38.3 °C (99.5 or 100.9 °F)[\[4\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-NC08-4)[\[5\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-CC09-5) \| \| [Hyperpyrexia](https://en.wikipedia.org/wiki/Fever#Hyperpyrexia "Fever") \| \>40.0 or 41.0 °C (104.0 or 105.8 °F)[\[6\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-6)[\[7\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-7) \| \| Note: The difference between fever and hyperthermia is the underlying mechanism. Different sources have different cut-offs for fever, hyperthermia and hyperpyrexia. \| \| \| [v](https://en.wikipedia.org/wiki/Template:HumanTemperature "Template:HumanTemperature") [t](https://en.wikipedia.org/wiki/Template_talk:HumanTemperature "Template talk:HumanTemperature") [e](https://en.wikipedia.org/wiki/Special:EditPage/Template:HumanTemperature "Special:EditPage/Template:HumanTemperature") \| \| Normal human body temperature (normothermia, euthermia) is the typical [temperature](https://en.wikipedia.org/wiki/Temperature "Temperature") range found in [humans](https://en.wikipedia.org/wiki/Humans "Humans"). The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F).[\[8\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kar2008-8)[\[9\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-pmid_37669046-9) Human body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the [body](https://en.wikipedia.org/wiki/Human_body "Human body") the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a [homeostatic](https://en.wikipedia.org/wiki/Homeostasis "Homeostasis") function known as [thermoregulation](https://en.wikipedia.org/wiki/Thermoregulation_in_humans "Thermoregulation in humans"), in which adjustment of temperature is triggered by the [central nervous system](https://en.wikipedia.org/wiki/Central_nervous_system "Central nervous system"). ## Methods of measurement \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=1 "Edit section: Methods of measurement")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/93/Clinical_thermometer_38.7.JPG/250px-Clinical_thermometer_38.7.JPG)](https://en.wikipedia.org/wiki/File:Clinical_thermometer_38.7.JPG) A [medical thermometer](https://en.wikipedia.org/wiki/Medical_thermometer "Medical thermometer") showing a temperature reading of 38.7 °C (101.7 °F) Taking a human's temperature is an initial part of a full [clinical examination](https://en.wikipedia.org/wiki/Clinical_examination "Clinical examination"). There are various types of [medical thermometers](https://en.wikipedia.org/wiki/Medical_thermometer "Medical thermometer"), as well as sites used for measurement, including: - Under the armpit (axillary temperature) - In the mouth (oral temperature) - In the [rectum](https://en.wikipedia.org/wiki/Rectum "Rectum") (rectal temperature) - In the ear (tympanic temperature) - On the skin of the forehead over the [temporal artery](https://en.wikipedia.org/wiki/Superficial_temporal_artery "Superficial temporal artery") - Using [heat flux sensors](https://en.wikipedia.org/wiki/Heat_flux_sensor "Heat flux sensor") ### Variations \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=2 "Edit section: Variations")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/2/21/Body_Temp_Variation.svg/330px-Body_Temp_Variation.svg.png)](https://en.wikipedia.org/wiki/File:Body_Temp_Variation.svg) Diurnal variation in body temperature, ranging from about 37.5 °C (99.5 °F) from 10 a.m. to 6 p.m., and falling to about 36.4 °C (97.5 °F) from 2 a.m. to 6 a.m. (Based on figure in entry for 'Animal Heat' in 11th edition of the [Encyclopædia Britannica](https://en.wikipedia.org/wiki/Encyclop%C3%A6dia_Britannica "Encyclopædia Britannica"), 1910) [Temperature control](https://en.wikipedia.org/wiki/Thermoregulation_in_humans "Thermoregulation in humans") ([thermoregulation](https://en.wikipedia.org/wiki/Thermoregulation "Thermoregulation")) is a [homeostatic](https://en.wikipedia.org/wiki/Homeostatic "Homeostatic") mechanism that keeps the organism at optimum [operating temperature](https://en.wikipedia.org/wiki/Operating_temperature "Operating temperature"), as the temperature affects the rate of [chemical reactions](https://en.wikipedia.org/wiki/Chemical_reaction "Chemical reaction"). In [humans](https://en.wikipedia.org/wiki/Human "Human"), the average internal temperature is widely accepted to be 37 °C (98.6 °F), a "normal" temperature established in the 1800s. But newer studies show that average internal temperature for men and women is 36.4 °C (97.5 °F).[\[10\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-10) No person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's [circadian rhythm](https://en.wikipedia.org/wiki/Circadian_rhythm "Circadian rhythm"). The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors.[\[11\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly-11) In addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.90 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day. Normal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F).[\[12\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Mac-12) This means that any oral temperature between 36.3 and 37.3 °C (97.3 and 99.1 °F) is likely to be normal.[\[13\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-13) The normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F).[\[8\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kar2008-8)[\[9\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-pmid_37669046-9) In adults a review of the literature has found a wider range of 33.2–38.2 °C (91.8–100.8 °F) for normal temperatures, depending on the gender and location measured.[\[14\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-SundLevander2002-14) Reported values vary depending on how it is measured: oral (under the tongue): 36.8 ± 0.4 °C (98.2 ± 0.7 °F),[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) internal ([rectal](https://en.wikipedia.org/wiki/Rectal "Rectal"), [vaginal](https://en.wikipedia.org/wiki/Vagina "Vagina")): 37.0 °C (98.6 °F).[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) A rectal or vaginal measurement taken directly inside the body cavity is typically slightly higher than oral measurement, and oral measurement is somewhat higher than skin measurement. Other places, such as under the arm or in the ear, produce different typical temperatures.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) While some people think of these averages as representing normal or ideal measurements, a wide range of temperatures has been found in healthy people.[\[5\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-CC09-5) The body temperature of a healthy person varies during the day by about 0.5 °C (0.9 °F) with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Other circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the [nadir](https://en.wikipedia.org/wiki/Nadir#Medicine "Nadir"), is one of the primary markers for [circadian rhythms](https://en.wikipedia.org/wiki/Circadian_rhythm "Circadian rhythm"). The body temperature also changes when a person is hungry, sleepy, sick, or cold. ### Natural rhythms \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=3 "Edit section: Natural rhythms")\] Body temperature normally fluctuates over the day following [circadian rhythms](https://en.wikipedia.org/wiki/Circadian_rhythm "Circadian rhythm"), with the lowest levels around 4 a.m. and the highest in the late afternoon, between 4:00 and 6:00 p.m. (assuming the person sleeps at night and stays awake during the day).[\[12\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Mac-12)[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Therefore, an oral temperature of 37.3 °C (99.1 °F) would, strictly speaking, be a normal, healthy temperature in the afternoon but not in the early morning.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) An individual's body temperature typically changes by about 0.5 °C (0.9 °F) between its highest and lowest points each day.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Body temperature is sensitive to many hormones, so women have a temperature rhythm that varies with the [menstrual cycle](https://en.wikipedia.org/wiki/Menstrual_cycle "Menstrual cycle"), called a circamensal rhythm.[\[11\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly-11)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] A woman's [basal body temperature](https://en.wikipedia.org/wiki/Basal_body_temperature "Basal body temperature") rises sharply after [ovulation](https://en.wikipedia.org/wiki/Ovulation "Ovulation"), as [estrogen](https://en.wikipedia.org/wiki/Estrogen "Estrogen") production decreases and [progesterone](https://en.wikipedia.org/wiki/Progesterone "Progesterone") increases. [Fertility awareness](https://en.wikipedia.org/wiki/Fertility_awareness "Fertility awareness") programs use this change to identify when a woman has ovulated to achieve or avoid [pregnancy](https://en.wikipedia.org/wiki/Pregnancy "Pregnancy"). During the [luteal phase](https://en.wikipedia.org/wiki/Luteal_phase "Luteal phase") of the menstrual cycle, both the lowest and the average temperatures are slightly higher than during other parts of the cycle. However, the amount that the temperature rises during each day is slightly lower than typical, so the highest temperature of the day is not very much higher than usual.[\[16\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly1-16)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] [Hormonal contraceptives](https://en.wikipedia.org/wiki/Hormonal_contraceptive "Hormonal contraceptive") both suppress the circamensal rhythm and raise the typical body temperature by about 0.6 °C (1.1 °F).[\[11\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly-11)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Temperature also may vary with the change of [seasons](https://en.wikipedia.org/wiki/Season "Season") during each year. This pattern is called a circannual rhythm.[\[16\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly1-16)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Studies of seasonal variations have produced inconsistent results. People living in different climates may have different seasonal patterns.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] It has been found that physically active individuals have larger changes in body temperature throughout the day. Physically active people have been reported to have lower body temperatures than their less active peers in the early morning and similar or higher body temperatures later in the day.[\[17\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Atkinson-17) With increased age, both average body temperature and the amount of daily variability in the body temperature tend to decrease.[\[16\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly1-16)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Elderly people may have a decreased ability to generate body heat during a fever, so even a [somewhat elevated temperature](https://en.wikipedia.org/wiki/Low-grade_fever "Low-grade fever") can indicate a serious underlying cause in [geriatrics](https://en.wikipedia.org/wiki/Geriatrics "Geriatrics"). One study suggested that the average body temperature has also decreased since the 1850s.[\[18\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-18) The study's authors believe the most likely explanation for the change is a reduction in inflammation at the population level due to decreased chronic infections and improved hygiene.[\[19\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-19) ### Measurement methods \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=4 "Edit section: Measurement methods")\] \| Method \| Women \| Men \| \|---\|---\|---\| \| Oral \| 33\.2–38.1 °C (91.8–100.6 °F) \| 35\.7–37.7 °C (96.3–99.9 °F) \| \| Rectal \| 36\.8–37.1 °C (98.2–98.8 °F) \| 36\.7–37.5 °C (98.1–99.5 °F) \| \| Tympanic \| 35\.7–37.5 °C (96.3–99.5 °F) \| 35\.5–37.5 °C (95.9–99.5 °F) \| \| Axillary \| 35\.5–37.0 °C (95.9–98.6 °F) \| \| Different methods used for measuring temperature produce different results. The temperature reading depends on which part of the body is being measured. The typical daytime temperatures among healthy adults are as follows: - Temperature in the rectum (rectal), vagina, or in the ear (tympanic) is about 37.5 °C (99.5 °F)[\[20\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Elert2005-20)\[[medical citation needed](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] - Temperature in the mouth (oral) is about 36.8 °C (98.2 °F)[\[12\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Mac-12) - Temperature under the arm (axillary) is about 36.5 °C (97.7 °F)[\[20\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Elert2005-20)\[[medical citation needed](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Generally, oral, rectal, gut, and core body temperatures, although slightly different, are well-correlated.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Oral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open. [Mouth breathing](https://en.wikipedia.org/wiki/Mouth_breathing "Mouth breathing"), cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures.[\[21\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-21) Each measurement method also has different normal ranges depending on sex.[\[14\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-SundLevander2002-14) ### Infrared thermometer \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=5 "Edit section: Infrared thermometer")\] Main article: [Infrared thermometer](https://en.wikipedia.org/wiki/Infrared_thermometer "Infrared thermometer") As of 2016, reviews of infrared thermometers have found them to be of variable accuracy.[\[22\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-22) This includes tympanic infrared thermometers in children.[\[23\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-23) ### Variations due to outside factors \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=6 "Edit section: Variations due to outside factors")\] Sleep disturbances also affect temperatures. Normally, body temperature drops significantly at a person's normal bedtime and throughout the night. Short-term [sleep deprivation](https://en.wikipedia.org/wiki/Sleep_deprivation "Sleep deprivation") produces a higher temperature at night than normal, but long-term sleep deprivation appears to reduce temperatures.[\[24\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-24) [Insomnia](https://en.wikipedia.org/wiki/Insomnia "Insomnia") and poor sleep quality are associated with smaller and later drops in body temperature.[\[25\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-25) Similarly, waking up unusually early, sleeping in, [jet lag](https://en.wikipedia.org/wiki/Jet_lag "Jet lag") and changes to [shift work](https://en.wikipedia.org/wiki/Shift_work "Shift work") schedules may affect body temperature. ## Concept \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=7 "Edit section: Concept")\] ### Fever \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=8 "Edit section: Fever")\] Main article: [Fever](https://en.wikipedia.org/wiki/Fever "Fever") A temperature setpoint is the level at which the body attempts to maintain its temperature. When the setpoint is raised, the result is a fever. Most fevers are caused by [infectious disease](https://en.wikipedia.org/wiki/Infectious_disease "Infectious disease") and can be lowered, if desired, with [antipyretic](https://en.wikipedia.org/wiki/Antipyretic "Antipyretic") medications. An early morning temperature higher than 37.3 °C (99.1 °F) or a late afternoon temperature higher than 37.7 °C (99.9 °F) is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Lower thresholds are sometimes appropriate for elderly people.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) The normal daily temperature variation is typically 0.5 °C (0.90 °F), but can be greater among people recovering from a fever.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) An organism at optimum temperature is considered afebrile, meaning "[without fever](https://en.wikipedia.org/wiki/Apyrexy "Apyrexy")".[\[26\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-26) If temperature is raised, but the setpoint is not raised, then the result is [hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia"). ### Hyperthermia \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=9 "Edit section: Hyperthermia")\] Main article: [Hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia") Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably. Hyperthermia at or above about 40 °C (104 °F) is a life-threatening medical emergency that requires immediate treatment. Common symptoms include headache, confusion, and fatigue. If sweating has resulted in dehydration, then the affected person may have dry, red skin. In a medical setting, mild hyperthermia is commonly called heat exhaustion or heat prostration; severe hyperthermia is called heat stroke. Heatstroke may come on suddenly, but it usually follows the untreated milder stages. Treatment involves cooling and rehydrating the body; fever-reducing drugs are useless for this condition. This may be done by moving out of direct sunlight to a cooler and shaded environment, drinking water, removing clothing that might keep heat close to the body, or sitting in front of a fan. Bathing in tepid or cool water, or even just [washing the face](https://en.wikipedia.org/wiki/Face_washing "Face washing") and other exposed areas of the skin, can be helpful. With fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers. ### Hypothermia \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=10 "Edit section: Hypothermia")\] Main article: [Hypothermia](https://en.wikipedia.org/wiki/Hypothermia "Hypothermia") In hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be [deliberately induced as a medical treatment](https://en.wikipedia.org/wiki/Therapeutic_hypothermia "Therapeutic hypothermia"). Symptoms usually appear when the body's core temperature drops by 1–2 °C (1.8–3.6 °F) below normal temperature. ### Basal body temperature \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=11 "Edit section: Basal body temperature")\] Main article: [Basal body temperature](https://en.wikipedia.org/wiki/Basal_body_temperature "Basal body temperature") Basal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature. In women, temperature differs at various points in the [menstrual cycle](https://en.wikipedia.org/wiki/Menstrual_cycle "Menstrual cycle"), and this can be used in the long term to track ovulation both to aid conception or avoid pregnancy. This process is called [fertility awareness](https://en.wikipedia.org/wiki/Fertility_awareness "Fertility awareness"). ### Core temperature \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=12 "Edit section: Core temperature")\] Core temperature, also called core body temperature, is the operating temperature of an [organism](https://en.wikipedia.org/wiki/Organism "Organism"), specifically in deep structures of the body such as the [liver](https://en.wikipedia.org/wiki/Liver "Liver"), in comparison to temperatures of peripheral tissues. Core temperature is normally maintained within a narrow range so that essential enzymatic reactions can occur. Significant core temperature elevation ([hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia")) or depression ([hypothermia](https://en.wikipedia.org/wiki/Hypothermia "Hypothermia")) over more than a brief period of time is fatal. Temperature examination in the [heart](https://en.wikipedia.org/wiki/Heart "Heart"), using a catheter, is the traditional [gold standard](https://en.wikipedia.org/wiki/Gold_standard_\(test\) "Gold standard (test)") measurement used to estimate core temperature (oral temperature is affected by hot or cold drinks, ambient temperature fluctuations as well as mouth-breathing). Since catheters are highly invasive, the generally accepted alternative for measuring core body temperature is through rectal measurements. Rectal temperature is expected to be approximately 1 °F (0.56 °C) higher than an oral temperature taken on the same person at the same time. Ear thermometers measure temperature from the [tympanic membrane](https://en.wikipedia.org/wiki/Tympanic_membrane "Tympanic membrane") using [infrared](https://en.wikipedia.org/wiki/Infrared "Infrared") sensors and also aim to measure core body temperature, since the blood supply of this membrane is directly shared with the [brain](https://en.wikipedia.org/wiki/Brain "Brain"). However, this method of measuring body temperature is not as accurate as rectal measurement and has a low sensitivity for fever, failing to determine three or four out of every ten fever measurements in children.[\[27\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Dodd-27) Ear temperature measurement may be acceptable for observing trends in body temperature but is less useful in consistently identifying and diagnosing fever. Until recently, direct measurement of core body temperature required either an ingestible device or surgical insertion of a probe. Therefore, a variety of indirect methods have commonly been used as the preferred alternative to these more accurate albeit more invasive methods. The [rectal](https://en.wikipedia.org/wiki/Rectum "Rectum") or [vaginal](https://en.wikipedia.org/wiki/Vagina "Vagina") temperature is generally considered to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible [thermistors](https://en.wikipedia.org/wiki/Thermistor "Thermistor") in [capsule](https://en.wikipedia.org/wiki/Capsule_\(pharmacy\) "Capsule (pharmacy)") form were produced, allowing the temperature inside the [digestive tract](https://en.wikipedia.org/wiki/Digestive_tract "Digestive tract") to be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement.[\[28\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-SciDirect-28) More recently, a new method using [heat flux sensors](https://en.wikipedia.org/wiki/Heat_flux_sensor "Heat flux sensor") have been developed. Several research papers show that its accuracy is similar to the invasive methods.[\[29\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-29)[\[30\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-30)[\[31\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-31) ### Internal variation \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=13 "Edit section: Internal variation")\] Measurement within the body finds internal variation temperatures as different as 21.5 °C (70.7 °F) for the [radial artery](https://en.wikipedia.org/wiki/Radial_artery "Radial artery") and 31.1 °C (88.0 °F) for the [brachial artery](https://en.wikipedia.org/wiki/Brachial_artery "Brachial artery").[\[32\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32) It has been observed that "chaos" has been "introduced into physiology by the fictitious assumption of a constant blood temperature".[\[32\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32) ## Temperature variation \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=14 "Edit section: Temperature variation")\] \| \| \| \|---\|---\| \| [![icon](https://upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/60px-Question_book-new.svg.png)](https://en.wikipedia.org/wiki/File:Question_book-new.svg) \| This section needs additional citations for [verification](https://en.wikipedia.org/wiki/Wikipedia:Verifiability "Wikipedia:Verifiability"). Please help [improve this article](https://en.wikipedia.org/wiki/Special:EditPage/Human_body_temperature "Special:EditPage/Human body temperature") by [adding citations to reliable sources](https://en.wikipedia.org/wiki/Help:Referencing_for_beginners "Help:Referencing for beginners") in this section. Unsourced material may be challenged and removed. (July 2014) ([Learn how and when to remove this message](https://en.wikipedia.org/wiki/Help:Maintenance_template_removal "Help:Maintenance template removal")) \| ### Hot \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=15 "Edit section: Hot")\] - 44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F).[\[33\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-33)[\[34\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-34) - 43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur. - 42 °C (107.6 °F) – Subject may turn red. They may become comatose, be in severe delirium, and convulsions can occur. - 41 °C (105.8 °F) – ([Medical emergency](https://en.wikipedia.org/wiki/Medical_emergency "Medical emergency")) – Fainting, severe headache, dizziness, confusion, hallucinations, delirium, and drowsiness can occur. There may also be [palpitations](https://en.wikipedia.org/wiki/Palpitations "Palpitations") and breathlessness. - 40 °C (104 °F) – Fainting, dehydration, weakness, headache, breathlessness, and dizziness may occur as well as profuse sweating. - 39 °C (102.2 °F) – Severe sweating, and red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer convulsions at this temperature. - 38 °C (100.4 °F) – (Classed as [hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia") if not caused by a [fever](https://en.wikipedia.org/wiki/Fever "Fever")) – Feeling hot, sweating, feeling thirsty, feeling very uncomfortable. - 37\.6 °C (99.7 °F) — Classed as a slight fever. May lose appetite, feeling hot, feeling uncomfortable, feeling thirsty. ### Normal \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=16 "Edit section: Normal")\] - 36\.5–37.5 °C (97.7–99.5 °F) is a typically reported range for normal body temperature.[\[8\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kar2008-8) ### Cold \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=17 "Edit section: Cold")\] - 35\.5 °C (95.9 °F) – Feeling cold, mild to moderate shivering. This can be a normal body temperature for sleeping. - 35 °C (95 °F) – Threshold for [hypothermia](https://en.wikipedia.org/wiki/Hypothermia "Hypothermia"). Intense shivering, numbness and bluish/grayness of the skin. There is the possibility of heart irritability. - 34 °C (93.2 °F) – Severe shivering, loss of movement of fingers, blueness, and confusion. Some behavioral changes may take place. - 33 °C (91.4 °F) – Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heartbeat, shallow breathing. Shivering may stop. The subject may be unresponsive to certain stimuli. - 32 °C (89.6 °F) – ([Medical emergency](https://en.wikipedia.org/wiki/Medical_emergency "Medical emergency")) – Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent. Reflex may be absent or very slight. - 31 °C (87.8 °F) – Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems. - 28 °C (82.4 °F) – Severe heart rhythm disturbances are likely and breathing may stop at any time. The person may appear to be dead.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] - 24–26 °C (75.2–78.8 °F) or less – Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures lower than 12.7 °C (54.9 °F).[\[35\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-35) The lowest recorded core temperature from a patient with accidental hypothermia who survived without neurological [sequelae](https://en.wikipedia.org/wiki/Sequela "Sequela") is 11.8 °C (53.2 °F).[\[36\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-36) There are non-verbal corporal cues that can hint at an individual experiencing a low body temperature, which can be used for those with [dysphasia](https://en.wikipedia.org/wiki/Dysphasia "Dysphasia") or infants.[\[37\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-37) Examples of non-[verbal](https://en.wiktionary.org/wiki/verbal "wikt:verbal") cues of [coldness](https://en.wikipedia.org/wiki/Coldness "Coldness") include stillness and being lethargic, unusual paleness of skin among light-skinned people, and, among males, shrinkage, and contraction of the [scrotum](https://en.wikipedia.org/wiki/Scrotum "Scrotum").[\[38\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-38) ## Effect of environment \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=18 "Edit section: Effect of environment")\] Environmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The [psychrometric temperature](https://en.wikipedia.org/wiki/Psychrometrics "Psychrometrics"), of which the [wet-bulb temperature](https://en.wikipedia.org/wiki/Wet-bulb_temperature "Wet-bulb temperature") is the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value consistent with human life. A 2022 study on the effect of heat on young people found that the critical wet-bulb temperature at which heat stress can no longer be compensated, Twb,crit, in young, healthy adults performing tasks at modest metabolic rates mimicking basic activities of daily life was much lower than the 35 °C (95 °F) usually assumed, at about 30.55 °C (86.99 °F) in 36–40 °C (97–104 °F) humid environments, but progressively decreased in hotter, dry ambient environments.[\[39\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-vecellio-39)[\[40\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-timperley-40) At low temperatures the body thermoregulates by generating heat, but this becomes unsustainable at extremely low temperatures. ## Historical understanding \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=19 "Edit section: Historical understanding")\] In the 19th century, most books quoted "blood heat" as 98 °F, until a study published the mean (but not the variance) of a large sample as 36.88 °C (98.38 °F).[\[41\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-41) Subsequently, that mean was widely quoted as "37 °C or 98.4 °F"[\[42\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-42)[\[43\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-43) until editors realized 37 °C is equal to 98.6 °F, not 98.4 °F. The 37 °C value was set by German physician [Carl Reinhold August Wunderlich](https://en.wikipedia.org/wiki/Carl_Reinhold_August_Wunderlich "Carl Reinhold August Wunderlich") in his 1868 book,[\[44\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-44) which put temperature charts into widespread clinical use.[\[45\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-45) Dictionaries and other sources\[[which?](https://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_words "Wikipedia:Avoid weasel words")\] that quoted these averages did add the word "about" to show that there is some variance, but generally did not state how wide the variance is.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] ## References \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=20 "Edit section: References")\] 1. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Rosen_1-0) Marx J (2006). Rosen's emergency medicine : concepts and clinical practice (6th ed.). Philadelphia: Mosby/Elsevier. p. 2239. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-323-02845-5](https://en.wikipedia.org/wiki/Special:BookSources/978-0-323-02845-5 "Special:BookSources/978-0-323-02845-5") . [OCLC](https://en.wikipedia.org/wiki/OCLC_\(identifier\) "OCLC (identifier)") [58533794](https://search.worldcat.org/oclc/58533794). 2. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-pmid18788094_2-0) Hutchison JS, Ward RE, Lacroix J, Hébert PC, Barnes MA, Bohn DJ, et al. (June 2008). "Hypothermia therapy after traumatic brain injury in children". The New England Journal of Medicine. 358 (23): 2447–56\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1056/NEJMoa0706930](https://doi.org/10.1056%2FNEJMoa0706930). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18525042](https://pubmed.ncbi.nlm.nih.gov/18525042). 3. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-3) Pryor JA, Prasad AS (2008). [Physiotherapy for Respiratory and Cardiac Problems: Adults and Paediatrics](https://books.google.ca/books?id=5n9fseWPLowC&pg=PA8). Elsevier Health Sciences. p. 8. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0702039744](https://en.wikipedia.org/wiki/Special:BookSources/978-0702039744 "Special:BookSources/978-0702039744") . "Body temperature is maintained within the range 36.5-37.5 °C. It is lowest in the early morning and highest in the afternoon." 4. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-NC08_4-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-NC08_4-1) Axelrod YK, Diringer MN (May 2008). "Temperature management in acute neurologic disorders". Neurologic Clinics. 26* (2): 585–603, xi. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.ncl.2008.02.005](https://doi.org/10.1016%2Fj.ncl.2008.02.005). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18514828](https://pubmed.ncbi.nlm.nih.gov/18514828). 5. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-CC09_5-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-CC09_5-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-CC09_5-2) Laupland KB (July 2009). "Fever in the critically ill medical patient". Critical Care Medicine. 37* (7 Suppl): S273-8. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1097/CCM.0b013e3181aa6117](https://doi.org/10.1097%2FCCM.0b013e3181aa6117). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [19535958](https://pubmed.ncbi.nlm.nih.gov/19535958). 6. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-6) Grunau BE, Wiens MO, Brubacher JR (September 2010). "Dantrolene in the treatment of MDMA-related hyperpyrexia: a systematic review". Cjem. 12 (5): 435–42\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1017/s1481803500012598](https://doi.org/10.1017%2Fs1481803500012598). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [20880437](https://pubmed.ncbi.nlm.nih.gov/20880437). "Dantrolene may also be associated with improved survival and reduced complications, especially in patients with extreme (≥ 42 °C) or severe (≥ 40 °C) hyperpyrexia" 7. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-7) Sharma HS, ed. (2007). [Neurobiology of Hyperthermia](https://books.google.com/books?id=Vk1UTlmEwrQC&pg=485#v=onepage&q=hyperpyrexia%20core%20temperature&f=false) (1st ed.). Elsevier. pp. 175–177, 485. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [9780080549996](https://en.wikipedia.org/wiki/Special:BookSources/9780080549996 "Special:BookSources/9780080549996") . Retrieved 19 November 2016. "Despite the myriad of complications associated with heat illness, an elevation of core temperature above 41.0 °C (often referred to as fever or hyperpyrexia) is the most widely recognized symptom of this syndrome." 8. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kar2008_8-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kar2008_8-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kar2008_8-2) Hutchison, James S.; et al. (June 2008). ["Hypothermia therapy after traumatic brain injury in children"](https://doi.org/10.1056%2FNEJMoa0706930). New England Journal of Medicine. 358* (23): 2447–2456\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1056/NEJMoa0706930](https://doi.org/10.1056%2FNEJMoa0706930). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18525042](https://pubmed.ncbi.nlm.nih.gov/18525042). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [46833](https://api.semanticscholar.org/CorpusID:46833). "We hypothesized that, as compared with normothermia (36.5 to 37.5°C), treatment with hypothermia..." 9. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-pmid_37669046_9-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-pmid_37669046_9-1) Ley, C; Heath, F; Hastie, T; Gao, Z; Protsiv, M; Parsonnet, J (5 September 2023). ["Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10481327). JAMA Internal Medicine. 183* (10): 1128–1135\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1001/jamainternmed.2023.4291](https://doi.org/10.1001%2Fjamainternmed.2023.4291). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [10481327](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10481327). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [37669046](https://pubmed.ncbi.nlm.nih.gov/37669046). 10. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-10) Weintraub, Karen (April 2020). ["Are Human Body Temperatures Cooling Down?"](https://www.scientificamerican.com/article/are-human-body-temperatures-cooling-down/). Scientific American. Retrieved 10 March 2022. 11. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly_11-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly_11-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly_11-2) Kelly, Greg S. (March 2007). ["Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease"](https://web.archive.org/web/20170809134435/http://altmedrev.com/publications/12/1/49.pdf) (PDF). Alternative Medicine Review. 12* (1): 49–62\. [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [17397267](https://pubmed.ncbi.nlm.nih.gov/17397267). Archived from [the original](http://www.altmedrev.com/publications/12/1/49.pdf) (PDF) on 2017-08-09. Retrieved 2016-12-28. 12. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Mac_12-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Mac_12-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Mac_12-2) Mackowiak, Philip A.; Wasserman, Steven S.; Levine, Myron M. (1992-09-23). "A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich". Journal of the American Medical Association. 268* (12): 1578–1580\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1001/jama.1992.03490120092034](https://doi.org/10.1001%2Fjama.1992.03490120092034). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [1302471](https://pubmed.ncbi.nlm.nih.gov/1302471). 13. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-13) Del Bene, Victor E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.), ["Temperature"](https://www.ncbi.nlm.nih.gov/books/NBK331/), Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.), Boston: Butterworths, [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-409-90077-4](https://en.wikipedia.org/wiki/Special:BookSources/978-0-409-90077-4 "Special:BookSources/978-0-409-90077-4") , [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [21250173](https://pubmed.ncbi.nlm.nih.gov/21250173), retrieved 2023-02-15 `{{citation}}`: CS1 maint: work parameter with ISBN ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN "Category:CS1 maint: work parameter with ISBN")) 14. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SundLevander2002_14-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SundLevander2002_14-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SundLevander2002_14-2) Sund-Levander, Märtha; Forsberg, Christina; Wahren, Lis Karen (2002). "Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review". Scandinavian Journal of Caring Sciences. 16* (2): 122–8\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1046/j.1471-6712.2002.00069.x](https://doi.org/10.1046%2Fj.1471-6712.2002.00069.x). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [12000664](https://pubmed.ncbi.nlm.nih.gov/12000664). 15. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-2) [d](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-3) [e](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-4) [f](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-5) [g](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-6) [h](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-7) [i](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-8) [j](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-9) Longo, Dan L., ed. (2011). [Harrison's principles of internal medicine](https://web.archive.org/web/20120429231736/http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4) (18th ed.). New York: McGraw-Hill. p. 142. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-07-174889-6](https://en.wikipedia.org/wiki/Special:BookSources/978-0-07-174889-6 "Special:BookSources/978-0-07-174889-6") . Archived from [the original](http://accessmedicine.com/resourceTOC.aspx?resourceID=4) on 2012-04-29. Retrieved 2012-03-16. 16. ^ [a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly1_16-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly1_16-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly1_16-2) Kelly, Greg S. (December 2006). ["Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging"](https://web.archive.org/web/20170808231722/http://altmedrev.com/publications/11/4/278.pdf) (PDF). Alternative Medicine Review. 11* (4): 278–93\. [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [17176167](https://pubmed.ncbi.nlm.nih.gov/17176167). Archived from [the original](http://www.altmedrev.com/publications/11/4/278.pdf) (PDF) on 2017-08-08. Retrieved 2016-12-28. 17. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Atkinson_17-0) Atkinson, G.; Coldwells, A.; Reilly, T.; Waterhouse, J. (January 1993). "A comparison of circadian rhythms in work performance between physically active and inactive subjects". Ergonomics. 36 (1–3\): 273–281\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1080/00140139308967882](https://doi.org/10.1080%2F00140139308967882). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [8440222](https://pubmed.ncbi.nlm.nih.gov/8440222). 18. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-18) Katz, Brigit (16 January 2020). ["Human Body Temperature Is Getting Cooler, Study Finds"](https://www.smithsonianmag.com/smart-news/human-body-temperature-getting-cooler-study-finds-180974006/). [Smithsonian](https://en.wikipedia.org/wiki/Smithsonian_\(magazine\) "Smithsonian (magazine)"). Retrieved 22 January 2020. 19. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-19) Protsiv, Myroslava; Ley, Catherine; Lankester, Joanna; Hastie, Trevor; [Parsonnet, Julie](https://en.wikipedia.org/wiki/Julie_Parsonnet "Julie Parsonnet") (2020-01-07). Jit, Mark; Franco, Eduardo; Waalen, Jill; Rühli, Frank (eds.). ["Decreasing human body temperature in the United States since the Industrial Revolution"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946399). eLife. 9 e49555. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.7554/eLife.49555](https://doi.org/10.7554%2FeLife.49555). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [2050-084X](https://search.worldcat.org/issn/2050-084X). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [6946399](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946399). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [31908267](https://pubmed.ncbi.nlm.nih.gov/31908267). 20. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Elert2005_20-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Elert2005_20-1) Wong, Lena (1997). Elert, Glenn (ed.). ["Temperature of a healthy human (body temperature)"](https://hypertextbook.com/facts/1997/LenaWong.shtml). The Physics Factbook. Retrieved 2022-01-25. 21. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-21)* Newman, B. H.; Martin, C. A. (October 2001). ["The effect of hot beverages, cold beverages, and chewing gum on oral temperature"](https://doi.org/10.1046%2Fj.1537-2995.2001.41101241.x). Transfusion. 41 (10): 1241–1243\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1046/j.1537-2995.2001.41101241.x](https://doi.org/10.1046%2Fj.1537-2995.2001.41101241.x). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [0041-1132](https://search.worldcat.org/issn/0041-1132). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [11606822](https://pubmed.ncbi.nlm.nih.gov/11606822). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [24681501](https://api.semanticscholar.org/CorpusID:24681501). 22. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-22) Kiekkas, P; Stefanopoulos, N; Bakalis, N; Kefaliakos, A; Karanikolas, M (April 2016). "Agreement of infrared temporal artery thermometry with other thermometry methods in adults: systematic review". Journal of Clinical Nursing. 25 (7–8\): 894–905\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1111/jocn.13117](https://doi.org/10.1111%2Fjocn.13117). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [26994990](https://pubmed.ncbi.nlm.nih.gov/26994990). 23. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-23) Zhen, C; Xia, Z; Long, L; Pu, Y (October 2014). "Accuracy of infrared ear thermometry in children: a meta-analysis and systematic review". Clinical Pediatrics. 53 (12): 1158–65\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1177/0009922814536774](https://doi.org/10.1177%2F0009922814536774). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [24879119](https://pubmed.ncbi.nlm.nih.gov/24879119). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [24982111](https://api.semanticscholar.org/CorpusID:24982111). 24. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-24) Paprocki, Jonathan (2012-12-18). ["Sleep deprivation disrupts regulation of body heat"](https://sleepeducation.org/sleep-deprivation-disrupts-regulation-body-heat/). Sleep Education. Retrieved 2023-02-15. 25. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-25) Lack, Leon C.; Gradisar, Michael; Van Someren, Eus J. W.; Wright, Helen R.; Lushington, Kurt (August 2008). "The relationship between insomnia and body temperatures". Sleep Medicine Reviews. 12 (4): 307–317\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.smrv.2008.02.003](https://doi.org/10.1016%2Fj.smrv.2008.02.003). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [1087-0792](https://search.worldcat.org/issn/1087-0792). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18603220](https://pubmed.ncbi.nlm.nih.gov/18603220). 26. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-26) ["Define Afebrile"](https://www.dictionary.com/browse/afebrile). 27. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Dodd_27-0) Dodd, Susanna R.; Lancaster, Gillian A.; Craig, Jean V.; Smyth, Rosalind L.; Williamson, Paula R. (April 2006). "In a systematic review, infrared ear thermometry for fever diagnosis in children finds poor sensitivity". Journal of Clinical Epidemiology. 59 (4): 354–7\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.jclinepi.2005.10.004](https://doi.org/10.1016%2Fj.jclinepi.2005.10.004). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [16549256](https://pubmed.ncbi.nlm.nih.gov/16549256). 28. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SciDirect_28-0) McKenzie, Jack E.; Osgood, David W. (2004). "Validation of a new telemetric core temperature monitor". Journal of Thermal Biology. 29 (7–8\): 605. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_\(identifier\) "Bibcode (identifier)"):[2004JTBio..29..605M](https://ui.adsabs.harvard.edu/abs/2004JTBio..29..605M). [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.jtherbio.2004.08.020](https://doi.org/10.1016%2Fj.jtherbio.2004.08.020). 29. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-29) Nidermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel (January 2014). ["Prediction of Human Core Body Temperature Using Non-Invasive Measurement Methods"](https://www.dora.lib4ri.ch/empa/islandora/object/empa%3A6081). International Journal of Biometeorology. 58 (1): 7–15\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_\(identifier\) "Bibcode (identifier)"):[2014IJBm...58....7N](https://ui.adsabs.harvard.edu/abs/2014IJBm...58....7N). [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1007/s00484-013-0687-2](https://doi.org/10.1007%2Fs00484-013-0687-2). [hdl](https://en.wikipedia.org/wiki/Hdl_\(identifier\) "Hdl (identifier)"):[20\.500.11850/80468](https://hdl.handle.net/20.500.11850%2F80468). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [23760405](https://pubmed.ncbi.nlm.nih.gov/23760405). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [11772946](https://api.semanticscholar.org/CorpusID:11772946). 30. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-30) Mendt, Stefan; Maggioni, Martina Ana; Nordine, Michael; Steinach, Mathias; Opatz, Oliver; Belavy, Daniel; Felsenberg, Dieter; Koch, Joachim; Shang, Peng; Hanns-Christian, Gunga; Stahn, Alexander (2017). "Circadian Rhythms in Bed Rest: Monitoring Core Body Temperature via Heat-Flux Approach Is Superior to Skin Surface Temperature". Chronobiology International. 34 (5): 666–676\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1080/07420528.2016.1224241](https://doi.org/10.1080%2F07420528.2016.1224241). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [27726448](https://pubmed.ncbi.nlm.nih.gov/27726448). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [205581198](https://api.semanticscholar.org/CorpusID:205581198). 31. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-31) Uth, Marc-Florian; Koch, Jochim; Sattler, Frank (2016). ["Body Core Temperature Sensing: Challenges and New Sensor Technologies"](https://doi.org/10.1016%2Fj.proeng.2016.11.154). Procedia Engineering. 168: 89–92\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.proeng.2016.11.154](https://doi.org/10.1016%2Fj.proeng.2016.11.154). 32. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-1) Bazett, H. C.; Love, L.; Newton, M.; Eisenberg, L.; Day, R.; Forster, R. (1948). "Temperature Changes in Blood Flowing in Arteries and Veins in Man". Journal of Applied Physiology. 1* (1): 3–19\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1152/jappl.1948.1.1.3](https://doi.org/10.1152%2Fjappl.1948.1.1.3). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [8750-7587](https://search.worldcat.org/issn/8750-7587). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18887571](https://pubmed.ncbi.nlm.nih.gov/18887571). 33. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-33) Chudler, Eric H. ["Biological Rhythms"](http://faculty.washington.edu/chudler/clock.html), Neuroscience for Kids, faculty.washington.edu 34. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-34) [temperature registered more than 115.7"](https://news.google.com/newspapers?id=y4IwAAAAIBAJ&sjid=t0QDAAAAIBAJ&pg=4281,2822445&dq=115.7+degrees&hl=en), Bulletin Journal, August 7, 1980 35. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-35) ["2-latek z Polski rekordzistą. Przeżył wychłodzenie poniżej 12 st. C."](https://dzienniknaukowy.pl/zdrowie/2-latek-z-polski-rekordzista-przezyl-wychlodzenie-ponizej-12-st-c) Dziennik Naukowy (in Polish). 5 December 2014. Retrieved 23 September 2022. 36. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-36) Mroczek, T.; Gladki, M.; Skalski, J. (26 June 2020). ["Successful resuscitation from accidental hypothermia of 11.8°C: where is the lower bound for human beings?"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886275). European Journal of Cardio-Thoracic Surgery. 58 (5): 1091–1092\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1093/ejcts/ezaa159](https://doi.org/10.1093%2Fejcts%2Fezaa159). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [7886275](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886275). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [33084865](https://pubmed.ncbi.nlm.nih.gov/33084865). 37. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-37) Tomita, K., et al. "Examination of factors affecting the intraoral perception of object size: A preliminary study." Journal of oral rehabilitation 44.4 (2017): 237–243. 38. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-38) Al-Tubaikh, Jarrah Ali. "Infectious Diseases and Tropical Medicine." Internal Medicine. Springer, Cham, 2017. 441–493. 39. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-vecellio_39-0) Vecellio, Daniel J.; Wolf, S. Tony; Cottle, Rachel M.; Kenney, W. Larry (2022-02-01). ["Evaluating the 35°C wet-bulb temperature adaptability threshold for young, healthy subjects (PSU HEAT Project)"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8799385). Journal of Applied Physiology. 132 (2): 340–345\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1152/japplphysiol.00738.2021](https://doi.org/10.1152%2Fjapplphysiol.00738.2021). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [8750-7587](https://search.worldcat.org/issn/8750-7587). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [8799385](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8799385). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [34913738](https://pubmed.ncbi.nlm.nih.gov/34913738). 40. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-timperley_40-0) Timperley, Jocelyn (31 July 2022). ["Why you need to worry about the 'wet-bulb temperature'"](https://www.theguardian.com/science/2022/jul/31/why-you-need-to-worry-about-the-wet-bulb-temperature). The Guardian. 41. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-41) [Inwit Publishing, Inc. and Inwit, LLC – Writings, Links and Software Demonstrations – A Fahrenheit–Celsius Activity](https://web.archive.org/web/20110713052807/http://www.inwit.com/inwit/writings/fahrenheitcelsiusactivity.html), inwit.com 42. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-42) [Oxford Dictionary of English](https://en.wikipedia.org/wiki/Oxford_Dictionary_of_English "Oxford Dictionary of English"), 2010 edition, entry on "blood heat" 43. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-43) [Collins English Dictionary](https://en.wikipedia.org/wiki/Collins_English_Dictionary "Collins English Dictionary"), 1979 edition, entry on ["blood heat"](https://www.collinsdictionary.com/us/dictionary/english/blood-heat) 44. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-44) Wunderlich, Carl Reinhold August (1868). [Das Verhalten der Eigenwärme in Krankheiten](https://archive.org/details/dasverhaltender00wundgoog) \[The behavior of the self-warmth in diseases\]. Leipzig: O. Wigand. ; its 1871 2nd edition translated into English and published with the title [On the temperature in diseases: a manual of medical thermometry](https://archive.org/details/ontemperaturein01wundgoog). 45. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-45) Fischetti, Mark (2018), "Graphic Science: Goodbye, 98.6", Scientific American, vol. 319, no. 6 (December) ![](https://en.wikipedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=1) Retrieved from "<https://en.wikipedia.org/w/index.php?title=Human_body_temperature&oldid=1344460278>" [Categories](https://en.wikipedia.org/wiki/Help:Category "Help:Category"): - [Human physiology](https://en.wikipedia.org/wiki/Category:Human_physiology "Category:Human physiology") - [Medical terminology](https://en.wikipedia.org/wiki/Category:Medical_terminology "Category:Medical terminology") - [Temperature](https://en.wikipedia.org/wiki/Category:Temperature "Category:Temperature") - [Physical examination](https://en.wikipedia.org/wiki/Category:Physical_examination "Category:Physical examination") - [Medical signs](https://en.wikipedia.org/wiki/Category:Medical_signs "Category:Medical signs") - [Thermoregulation](https://en.wikipedia.org/wiki/Category:Thermoregulation "Category:Thermoregulation") - [Thermometers](https://en.wikipedia.org/wiki/Category:Thermometers "Category:Thermometers") Hidden categories: - [All articles lacking reliable references](https://en.wikipedia.org/wiki/Category:All_articles_lacking_reliable_references "Category:All articles lacking reliable references") - [Articles lacking reliable references from November 2017](https://en.wikipedia.org/wiki/Category:Articles_lacking_reliable_references_from_November_2017 "Category:Articles lacking reliable references from November 2017") - [CS1 maint: work parameter with ISBN](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN "Category:CS1 maint: work parameter with ISBN") - [CS1 Polish-language sources (pl)](https://en.wikipedia.org/wiki/Category:CS1_Polish-language_sources_\(pl\) "Category:CS1 Polish-language sources (pl)") - [Articles with short description](https://en.wikipedia.org/wiki/Category:Articles_with_short_description "Category:Articles with short description") - [Short description matches Wikidata](https://en.wikipedia.org/wiki/Category:Short_description_matches_Wikidata "Category:Short description matches Wikidata") - [Articles needing additional medical references from November 2022](https://en.wikipedia.org/wiki/Category:Articles_needing_additional_medical_references_from_November_2022 "Category:Articles needing additional medical references from November 2022") - [All articles needing additional references](https://en.wikipedia.org/wiki/Category:All_articles_needing_additional_references "Category:All articles needing additional references") - [Articles requiring reliable medical sources](https://en.wikipedia.org/wiki/Category:Articles_requiring_reliable_medical_sources "Category:Articles requiring reliable medical sources") - [All articles with unsourced statements](https://en.wikipedia.org/wiki/Category:All_articles_with_unsourced_statements "Category:All articles with unsourced statements") - [Articles with unsourced statements from April 2021](https://en.wikipedia.org/wiki/Category:Articles_with_unsourced_statements_from_April_2021 "Category:Articles with unsourced statements from April 2021") - [Articles with unsourced statements from November 2017](https://en.wikipedia.org/wiki/Category:Articles_with_unsourced_statements_from_November_2017 "Category:Articles with unsourced statements from November 2017") - [Articles needing additional references from July 2014](https://en.wikipedia.org/wiki/Category:Articles_needing_additional_references_from_July_2014 "Category:Articles needing additional references from July 2014") - [All articles with specifically marked weasel-worded phrases](https://en.wikipedia.org/wiki/Category:All_articles_with_specifically_marked_weasel-worded_phrases "Category:All articles with specifically marked weasel-worded phrases") - [Articles with specifically marked weasel-worded phrases from October 2020](https://en.wikipedia.org/wiki/Category:Articles_with_specifically_marked_weasel-worded_phrases_from_October_2020 "Category:Articles with specifically marked weasel-worded phrases from October 2020") - [Articles with unsourced statements from June 2021](https://en.wikipedia.org/wiki/Category:Articles_with_unsourced_statements_from_June_2021 "Category:Articles with unsourced statements from June 2021") - This page was last edited on 20 March 2026, at 16:06 (UTC). - Text is available under the [Creative Commons Attribution-ShareAlike 4.0 License](https://en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License "Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License"); additional terms may apply. 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Readable Markdown	Normal human body temperature (normothermia, euthermia) is the typical [temperature](https://en.wikipedia.org/wiki/Temperature "Temperature") range found in [humans](https://en.wikipedia.org/wiki/Humans "Humans"). The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F).[\[8\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kar2008-8)[\[9\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-pmid_37669046-9) Human body temperature varies. It depends on sex, age, time of day, exertion level, health status (such as illness and menstruation), what part of the [body](https://en.wikipedia.org/wiki/Human_body "Human body") the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. Body temperature is kept in the normal range by a [homeostatic](https://en.wikipedia.org/wiki/Homeostasis "Homeostasis") function known as [thermoregulation](https://en.wikipedia.org/wiki/Thermoregulation_in_humans "Thermoregulation in humans"), in which adjustment of temperature is triggered by the [central nervous system](https://en.wikipedia.org/wiki/Central_nervous_system "Central nervous system"). ## Methods of measurement \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=1 "Edit section: Methods of measurement")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/93/Clinical_thermometer_38.7.JPG/250px-Clinical_thermometer_38.7.JPG)](https://en.wikipedia.org/wiki/File:Clinical_thermometer_38.7.JPG) A [medical thermometer](https://en.wikipedia.org/wiki/Medical_thermometer "Medical thermometer") showing a temperature reading of 38.7 °C (101.7 °F) Taking a human's temperature is an initial part of a full [clinical examination](https://en.wikipedia.org/wiki/Clinical_examination "Clinical examination"). There are various types of [medical thermometers](https://en.wikipedia.org/wiki/Medical_thermometer "Medical thermometer"), as well as sites used for measurement, including: - Under the armpit (axillary temperature) - In the mouth (oral temperature) - In the [rectum](https://en.wikipedia.org/wiki/Rectum "Rectum") (rectal temperature) - In the ear (tympanic temperature) - On the skin of the forehead over the [temporal artery](https://en.wikipedia.org/wiki/Superficial_temporal_artery "Superficial temporal artery") - Using [heat flux sensors](https://en.wikipedia.org/wiki/Heat_flux_sensor "Heat flux sensor") [![](https://upload.wikimedia.org/wikipedia/commons/thumb/2/21/Body_Temp_Variation.svg/330px-Body_Temp_Variation.svg.png)](https://en.wikipedia.org/wiki/File:Body_Temp_Variation.svg) Diurnal variation in body temperature, ranging from about 37.5 °C (99.5 °F) from 10 a.m. to 6 p.m., and falling to about 36.4 °C (97.5 °F) from 2 a.m. to 6 a.m. (Based on figure in entry for 'Animal Heat' in 11th edition of the [Encyclopædia Britannica](https://en.wikipedia.org/wiki/Encyclop%C3%A6dia_Britannica "Encyclopædia Britannica"), 1910) [Temperature control](https://en.wikipedia.org/wiki/Thermoregulation_in_humans "Thermoregulation in humans") ([thermoregulation](https://en.wikipedia.org/wiki/Thermoregulation "Thermoregulation")) is a [homeostatic](https://en.wikipedia.org/wiki/Homeostatic "Homeostatic") mechanism that keeps the organism at optimum [operating temperature](https://en.wikipedia.org/wiki/Operating_temperature "Operating temperature"), as the temperature affects the rate of [chemical reactions](https://en.wikipedia.org/wiki/Chemical_reaction "Chemical reaction"). In [humans](https://en.wikipedia.org/wiki/Human "Human"), the average internal temperature is widely accepted to be 37 °C (98.6 °F), a "normal" temperature established in the 1800s. But newer studies show that average internal temperature for men and women is 36.4 °C (97.5 °F).[\[10\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-10) No person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's [circadian rhythm](https://en.wikipedia.org/wiki/Circadian_rhythm "Circadian rhythm"). The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures change according to activities and external factors.[\[11\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly-11) In addition to varying throughout the day, normal body temperature may also differ as much as 0.5 °C (0.90 °F) from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day. Normal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F).[\[12\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Mac-12) This means that any oral temperature between 36.3 and 37.3 °C (97.3 and 99.1 °F) is likely to be normal.[\[13\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-13) The normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F).[\[8\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kar2008-8)[\[9\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-pmid_37669046-9) In adults a review of the literature has found a wider range of 33.2–38.2 °C (91.8–100.8 °F) for normal temperatures, depending on the gender and location measured.[\[14\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-SundLevander2002-14) Reported values vary depending on how it is measured: oral (under the tongue): 36.8 ± 0.4 °C (98.2 ± 0.7 °F),[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) internal ([rectal](https://en.wikipedia.org/wiki/Rectal "Rectal"), [vaginal](https://en.wikipedia.org/wiki/Vagina "Vagina")): 37.0 °C (98.6 °F).[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) A rectal or vaginal measurement taken directly inside the body cavity is typically slightly higher than oral measurement, and oral measurement is somewhat higher than skin measurement. Other places, such as under the arm or in the ear, produce different typical temperatures.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) While some people think of these averages as representing normal or ideal measurements, a wide range of temperatures has been found in healthy people.[\[5\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-CC09-5) The body temperature of a healthy person varies during the day by about 0.5 °C (0.9 °F) with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Other circumstances also affect the body's temperature. The core body temperature of an individual tends to have the lowest value in the second half of the sleep cycle; the lowest point, called the [nadir](https://en.wikipedia.org/wiki/Nadir#Medicine "Nadir"), is one of the primary markers for [circadian rhythms](https://en.wikipedia.org/wiki/Circadian_rhythm "Circadian rhythm"). The body temperature also changes when a person is hungry, sleepy, sick, or cold. Body temperature normally fluctuates over the day following [circadian rhythms](https://en.wikipedia.org/wiki/Circadian_rhythm "Circadian rhythm"), with the lowest levels around 4 a.m. and the highest in the late afternoon, between 4:00 and 6:00 p.m. (assuming the person sleeps at night and stays awake during the day).[\[12\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Mac-12)[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Therefore, an oral temperature of 37.3 °C (99.1 °F) would, strictly speaking, be a normal, healthy temperature in the afternoon but not in the early morning.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) An individual's body temperature typically changes by about 0.5 °C (0.9 °F) between its highest and lowest points each day.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Body temperature is sensitive to many hormones, so women have a temperature rhythm that varies with the [menstrual cycle](https://en.wikipedia.org/wiki/Menstrual_cycle "Menstrual cycle"), called a circamensal rhythm.[\[11\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly-11)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] A woman's [basal body temperature](https://en.wikipedia.org/wiki/Basal_body_temperature "Basal body temperature") rises sharply after [ovulation](https://en.wikipedia.org/wiki/Ovulation "Ovulation"), as [estrogen](https://en.wikipedia.org/wiki/Estrogen "Estrogen") production decreases and [progesterone](https://en.wikipedia.org/wiki/Progesterone "Progesterone") increases. [Fertility awareness](https://en.wikipedia.org/wiki/Fertility_awareness "Fertility awareness") programs use this change to identify when a woman has ovulated to achieve or avoid [pregnancy](https://en.wikipedia.org/wiki/Pregnancy "Pregnancy"). During the [luteal phase](https://en.wikipedia.org/wiki/Luteal_phase "Luteal phase") of the menstrual cycle, both the lowest and the average temperatures are slightly higher than during other parts of the cycle. However, the amount that the temperature rises during each day is slightly lower than typical, so the highest temperature of the day is not very much higher than usual.[\[16\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly1-16)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] [Hormonal contraceptives](https://en.wikipedia.org/wiki/Hormonal_contraceptive "Hormonal contraceptive") both suppress the circamensal rhythm and raise the typical body temperature by about 0.6 °C (1.1 °F).[\[11\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly-11)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Temperature also may vary with the change of [seasons](https://en.wikipedia.org/wiki/Season "Season") during each year. This pattern is called a circannual rhythm.[\[16\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly1-16)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Studies of seasonal variations have produced inconsistent results. People living in different climates may have different seasonal patterns.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] It has been found that physically active individuals have larger changes in body temperature throughout the day. Physically active people have been reported to have lower body temperatures than their less active peers in the early morning and similar or higher body temperatures later in the day.[\[17\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Atkinson-17) With increased age, both average body temperature and the amount of daily variability in the body temperature tend to decrease.[\[16\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kelly1-16)\[[unreliable medical source?](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Elderly people may have a decreased ability to generate body heat during a fever, so even a [somewhat elevated temperature](https://en.wikipedia.org/wiki/Low-grade_fever "Low-grade fever") can indicate a serious underlying cause in [geriatrics](https://en.wikipedia.org/wiki/Geriatrics "Geriatrics"). One study suggested that the average body temperature has also decreased since the 1850s.[\[18\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-18) The study's authors believe the most likely explanation for the change is a reduction in inflammation at the population level due to decreased chronic infections and improved hygiene.[\[19\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-19) ### Measurement methods \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=4 "Edit section: Measurement methods")\] \| Method \| Women \| Men \| \|---\|---\|---\| \| Oral \| 33\.2–38.1 °C (91.8–100.6 °F) \| 35\.7–37.7 °C (96.3–99.9 °F) \| \| Rectal \| 36\.8–37.1 °C (98.2–98.8 °F) \| 36\.7–37.5 °C (98.1–99.5 °F) \| \| Tympanic \| 35\.7–37.5 °C (96.3–99.5 °F) \| 35\.5–37.5 °C (95.9–99.5 °F) \| \| Axillary \| 35\.5–37.0 °C (95.9–98.6 °F) \| \| Different methods used for measuring temperature produce different results. The temperature reading depends on which part of the body is being measured. The typical daytime temperatures among healthy adults are as follows: - Temperature in the rectum (rectal), vagina, or in the ear (tympanic) is about 37.5 °C (99.5 °F)[\[20\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Elert2005-20)\[[medical citation needed](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] - Temperature in the mouth (oral) is about 36.8 °C (98.2 °F)[\[12\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Mac-12) - Temperature under the arm (axillary) is about 36.5 °C (97.7 °F)[\[20\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Elert2005-20)\[[medical citation needed](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources_\(medicine\) "Wikipedia:Identifying reliable sources (medicine)")\] Generally, oral, rectal, gut, and core body temperatures, although slightly different, are well-correlated.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Oral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open. [Mouth breathing](https://en.wikipedia.org/wiki/Mouth_breathing "Mouth breathing"), cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures.[\[21\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-21) Each measurement method also has different normal ranges depending on sex.[\[14\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-SundLevander2002-14) ### Infrared thermometer \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=5 "Edit section: Infrared thermometer")\] As of 2016, reviews of infrared thermometers have found them to be of variable accuracy.[\[22\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-22) This includes tympanic infrared thermometers in children.[\[23\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-23) ### Variations due to outside factors \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=6 "Edit section: Variations due to outside factors")\] Sleep disturbances also affect temperatures. Normally, body temperature drops significantly at a person's normal bedtime and throughout the night. Short-term [sleep deprivation](https://en.wikipedia.org/wiki/Sleep_deprivation "Sleep deprivation") produces a higher temperature at night than normal, but long-term sleep deprivation appears to reduce temperatures.[\[24\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-24) [Insomnia](https://en.wikipedia.org/wiki/Insomnia "Insomnia") and poor sleep quality are associated with smaller and later drops in body temperature.[\[25\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-25) Similarly, waking up unusually early, sleeping in, [jet lag](https://en.wikipedia.org/wiki/Jet_lag "Jet lag") and changes to [shift work](https://en.wikipedia.org/wiki/Shift_work "Shift work") schedules may affect body temperature. A temperature setpoint is the level at which the body attempts to maintain its temperature. When the setpoint is raised, the result is a fever. Most fevers are caused by [infectious disease](https://en.wikipedia.org/wiki/Infectious_disease "Infectious disease") and can be lowered, if desired, with [antipyretic](https://en.wikipedia.org/wiki/Antipyretic "Antipyretic") medications. An early morning temperature higher than 37.3 °C (99.1 °F) or a late afternoon temperature higher than 37.7 °C (99.9 °F) is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) Lower thresholds are sometimes appropriate for elderly people.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) The normal daily temperature variation is typically 0.5 °C (0.90 °F), but can be greater among people recovering from a fever.[\[15\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Longo-15) An organism at optimum temperature is considered afebrile, meaning "[without fever](https://en.wikipedia.org/wiki/Apyrexy "Apyrexy")".[\[26\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-26) If temperature is raised, but the setpoint is not raised, then the result is [hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia"). Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably. Hyperthermia at or above about 40 °C (104 °F) is a life-threatening medical emergency that requires immediate treatment. Common symptoms include headache, confusion, and fatigue. If sweating has resulted in dehydration, then the affected person may have dry, red skin. In a medical setting, mild hyperthermia is commonly called heat exhaustion or heat prostration; severe hyperthermia is called heat stroke. Heatstroke may come on suddenly, but it usually follows the untreated milder stages. Treatment involves cooling and rehydrating the body; fever-reducing drugs are useless for this condition. This may be done by moving out of direct sunlight to a cooler and shaded environment, drinking water, removing clothing that might keep heat close to the body, or sitting in front of a fan. Bathing in tepid or cool water, or even just [washing the face](https://en.wikipedia.org/wiki/Face_washing "Face washing") and other exposed areas of the skin, can be helpful. With fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers. In hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be [deliberately induced as a medical treatment](https://en.wikipedia.org/wiki/Therapeutic_hypothermia "Therapeutic hypothermia"). Symptoms usually appear when the body's core temperature drops by 1–2 °C (1.8–3.6 °F) below normal temperature. ### Basal body temperature \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=11 "Edit section: Basal body temperature")\] Basal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature. In women, temperature differs at various points in the [menstrual cycle](https://en.wikipedia.org/wiki/Menstrual_cycle "Menstrual cycle"), and this can be used in the long term to track ovulation both to aid conception or avoid pregnancy. This process is called [fertility awareness](https://en.wikipedia.org/wiki/Fertility_awareness "Fertility awareness"). Core temperature, also called core body temperature, is the operating temperature of an [organism](https://en.wikipedia.org/wiki/Organism "Organism"), specifically in deep structures of the body such as the [liver](https://en.wikipedia.org/wiki/Liver "Liver"), in comparison to temperatures of peripheral tissues. Core temperature is normally maintained within a narrow range so that essential enzymatic reactions can occur. Significant core temperature elevation ([hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia")) or depression ([hypothermia](https://en.wikipedia.org/wiki/Hypothermia "Hypothermia")) over more than a brief period of time is fatal. Temperature examination in the [heart](https://en.wikipedia.org/wiki/Heart "Heart"), using a catheter, is the traditional [gold standard](https://en.wikipedia.org/wiki/Gold_standard_\(test\) "Gold standard (test)") measurement used to estimate core temperature (oral temperature is affected by hot or cold drinks, ambient temperature fluctuations as well as mouth-breathing). Since catheters are highly invasive, the generally accepted alternative for measuring core body temperature is through rectal measurements. Rectal temperature is expected to be approximately 1 °F (0.56 °C) higher than an oral temperature taken on the same person at the same time. Ear thermometers measure temperature from the [tympanic membrane](https://en.wikipedia.org/wiki/Tympanic_membrane "Tympanic membrane") using [infrared](https://en.wikipedia.org/wiki/Infrared "Infrared") sensors and also aim to measure core body temperature, since the blood supply of this membrane is directly shared with the [brain](https://en.wikipedia.org/wiki/Brain "Brain"). However, this method of measuring body temperature is not as accurate as rectal measurement and has a low sensitivity for fever, failing to determine three or four out of every ten fever measurements in children.[\[27\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Dodd-27) Ear temperature measurement may be acceptable for observing trends in body temperature but is less useful in consistently identifying and diagnosing fever. Until recently, direct measurement of core body temperature required either an ingestible device or surgical insertion of a probe. Therefore, a variety of indirect methods have commonly been used as the preferred alternative to these more accurate albeit more invasive methods. The [rectal](https://en.wikipedia.org/wiki/Rectum "Rectum") or [vaginal](https://en.wikipedia.org/wiki/Vagina "Vagina") temperature is generally considered to give the most accurate assessment of core body temperature, particularly in hypothermia. In the early 2000s, ingestible [thermistors](https://en.wikipedia.org/wiki/Thermistor "Thermistor") in [capsule](https://en.wikipedia.org/wiki/Capsule_\(pharmacy\) "Capsule (pharmacy)") form were produced, allowing the temperature inside the [digestive tract](https://en.wikipedia.org/wiki/Digestive_tract "Digestive tract") to be transmitted to an external receiver; one study found that these were comparable in accuracy to rectal temperature measurement.[\[28\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-SciDirect-28) More recently, a new method using [heat flux sensors](https://en.wikipedia.org/wiki/Heat_flux_sensor "Heat flux sensor") have been developed. Several research papers show that its accuracy is similar to the invasive methods.[\[29\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-29)[\[30\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-30)[\[31\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-31) Measurement within the body finds internal variation temperatures as different as 21.5 °C (70.7 °F) for the [radial artery](https://en.wikipedia.org/wiki/Radial_artery "Radial artery") and 31.1 °C (88.0 °F) for the [brachial artery](https://en.wikipedia.org/wiki/Brachial_artery "Brachial artery").[\[32\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32) It has been observed that "chaos" has been "introduced into physiology by the fictitious assumption of a constant blood temperature".[\[32\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319-32) ## Temperature variation \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=14 "Edit section: Temperature variation")\] - 44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F).[\[33\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-33)[\[34\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-34) - 43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur. - 42 °C (107.6 °F) – Subject may turn red. They may become comatose, be in severe delirium, and convulsions can occur. - 41 °C (105.8 °F) – ([Medical emergency](https://en.wikipedia.org/wiki/Medical_emergency "Medical emergency")) – Fainting, severe headache, dizziness, confusion, hallucinations, delirium, and drowsiness can occur. There may also be [palpitations](https://en.wikipedia.org/wiki/Palpitations "Palpitations") and breathlessness. - 40 °C (104 °F) – Fainting, dehydration, weakness, headache, breathlessness, and dizziness may occur as well as profuse sweating. - 39 °C (102.2 °F) – Severe sweating, and red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer convulsions at this temperature. - 38 °C (100.4 °F) – (Classed as [hyperthermia](https://en.wikipedia.org/wiki/Hyperthermia "Hyperthermia") if not caused by a [fever](https://en.wikipedia.org/wiki/Fever "Fever")) – Feeling hot, sweating, feeling thirsty, feeling very uncomfortable. - 37\.6 °C (99.7 °F) — Classed as a slight fever. May lose appetite, feeling hot, feeling uncomfortable, feeling thirsty. - 36\.5–37.5 °C (97.7–99.5 °F) is a typically reported range for normal body temperature.[\[8\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-Kar2008-8) - 35\.5 °C (95.9 °F) – Feeling cold, mild to moderate shivering. This can be a normal body temperature for sleeping. - 35 °C (95 °F) – Threshold for [hypothermia](https://en.wikipedia.org/wiki/Hypothermia "Hypothermia"). Intense shivering, numbness and bluish/grayness of the skin. There is the possibility of heart irritability. - 34 °C (93.2 °F) – Severe shivering, loss of movement of fingers, blueness, and confusion. Some behavioral changes may take place. - 33 °C (91.4 °F) – Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heartbeat, shallow breathing. Shivering may stop. The subject may be unresponsive to certain stimuli. - 32 °C (89.6 °F) – ([Medical emergency](https://en.wikipedia.org/wiki/Medical_emergency "Medical emergency")) – Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent. Reflex may be absent or very slight. - 31 °C (87.8 °F) – Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems. - 28 °C (82.4 °F) – Severe heart rhythm disturbances are likely and breathing may stop at any time. The person may appear to be dead.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] - 24–26 °C (75.2–78.8 °F) or less – Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures lower than 12.7 °C (54.9 °F).[\[35\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-35) The lowest recorded core temperature from a patient with accidental hypothermia who survived without neurological [sequelae](https://en.wikipedia.org/wiki/Sequela "Sequela") is 11.8 °C (53.2 °F).[\[36\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-36) There are non-verbal corporal cues that can hint at an individual experiencing a low body temperature, which can be used for those with [dysphasia](https://en.wikipedia.org/wiki/Dysphasia "Dysphasia") or infants.[\[37\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-37) Examples of non-[verbal](https://en.wiktionary.org/wiki/verbal "wikt:verbal") cues of [coldness](https://en.wikipedia.org/wiki/Coldness "Coldness") include stillness and being lethargic, unusual paleness of skin among light-skinned people, and, among males, shrinkage, and contraction of the [scrotum](https://en.wikipedia.org/wiki/Scrotum "Scrotum").[\[38\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-38) ## Effect of environment \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=18 "Edit section: Effect of environment")\] Environmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The [psychrometric temperature](https://en.wikipedia.org/wiki/Psychrometrics "Psychrometrics"), of which the [wet-bulb temperature](https://en.wikipedia.org/wiki/Wet-bulb_temperature "Wet-bulb temperature") is the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value consistent with human life. A 2022 study on the effect of heat on young people found that the critical wet-bulb temperature at which heat stress can no longer be compensated, Twb,crit, in young, healthy adults performing tasks at modest metabolic rates mimicking basic activities of daily life was much lower than the 35 °C (95 °F) usually assumed, at about 30.55 °C (86.99 °F) in 36–40 °C (97–104 °F) humid environments, but progressively decreased in hotter, dry ambient environments.[\[39\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-vecellio-39)[\[40\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-timperley-40) At low temperatures the body thermoregulates by generating heat, but this becomes unsustainable at extremely low temperatures. ## Historical understanding \[[edit](https://en.wikipedia.org/w/index.php?title=Human_body_temperature&action=edit&section=19 "Edit section: Historical understanding")\] In the 19th century, most books quoted "blood heat" as 98 °F, until a study published the mean (but not the variance) of a large sample as 36.88 °C (98.38 °F).[\[41\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-41) Subsequently, that mean was widely quoted as "37 °C or 98.4 °F"[\[42\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-42)[\[43\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-43) until editors realized 37 °C is equal to 98.6 °F, not 98.4 °F. The 37 °C value was set by German physician [Carl Reinhold August Wunderlich](https://en.wikipedia.org/wiki/Carl_Reinhold_August_Wunderlich "Carl Reinhold August Wunderlich") in his 1868 book,[\[44\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-44) which put temperature charts into widespread clinical use.[\[45\]](https://en.wikipedia.org/wiki/Human_body_temperature#cite_note-45) Dictionaries and other sources\[[which?](https://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_words "Wikipedia:Avoid weasel words")\] that quoted these averages did add the word "about" to show that there is some variance, but generally did not state how wide the variance is.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] 1. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Rosen_1-0) Marx J (2006). Rosen's emergency medicine : concepts and clinical practice (6th ed.). Philadelphia: Mosby/Elsevier. p. 2239. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-323-02845-5](https://en.wikipedia.org/wiki/Special:BookSources/978-0-323-02845-5 "Special:BookSources/978-0-323-02845-5") . [OCLC](https://en.wikipedia.org/wiki/OCLC_\(identifier\) "OCLC (identifier)") [58533794](https://search.worldcat.org/oclc/58533794). 2. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-pmid18788094_2-0) Hutchison JS, Ward RE, Lacroix J, Hébert PC, Barnes MA, Bohn DJ, et al. (June 2008). "Hypothermia therapy after traumatic brain injury in children". The New England Journal of Medicine. 358 (23): 2447–56\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1056/NEJMoa0706930](https://doi.org/10.1056%2FNEJMoa0706930). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18525042](https://pubmed.ncbi.nlm.nih.gov/18525042). 3. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-3) Pryor JA, Prasad AS (2008). [Physiotherapy for Respiratory and Cardiac Problems: Adults and Paediatrics](https://books.google.ca/books?id=5n9fseWPLowC&pg=PA8). Elsevier Health Sciences. p. 8. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0702039744](https://en.wikipedia.org/wiki/Special:BookSources/978-0702039744 "Special:BookSources/978-0702039744") . "Body temperature is maintained within the range 36.5-37.5 °C. It is lowest in the early morning and highest in the afternoon." 4. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-NC08_4-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-NC08_4-1) Axelrod YK, Diringer MN (May 2008). "Temperature management in acute neurologic disorders". Neurologic Clinics. 26* (2): 585–603, xi. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.ncl.2008.02.005](https://doi.org/10.1016%2Fj.ncl.2008.02.005). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18514828](https://pubmed.ncbi.nlm.nih.gov/18514828). 5. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-CC09_5-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-CC09_5-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-CC09_5-2) Laupland KB (July 2009). "Fever in the critically ill medical patient". Critical Care Medicine. 37* (7 Suppl): S273-8. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1097/CCM.0b013e3181aa6117](https://doi.org/10.1097%2FCCM.0b013e3181aa6117). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [19535958](https://pubmed.ncbi.nlm.nih.gov/19535958). 6. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-6) Grunau BE, Wiens MO, Brubacher JR (September 2010). "Dantrolene in the treatment of MDMA-related hyperpyrexia: a systematic review". Cjem. 12 (5): 435–42\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1017/s1481803500012598](https://doi.org/10.1017%2Fs1481803500012598). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [20880437](https://pubmed.ncbi.nlm.nih.gov/20880437). "Dantrolene may also be associated with improved survival and reduced complications, especially in patients with extreme (≥ 42 °C) or severe (≥ 40 °C) hyperpyrexia" 7. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-7) Sharma HS, ed. (2007). [Neurobiology of Hyperthermia](https://books.google.com/books?id=Vk1UTlmEwrQC&pg=485#v=onepage&q=hyperpyrexia%20core%20temperature&f=false) (1st ed.). Elsevier. pp. 175–177, 485. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [9780080549996](https://en.wikipedia.org/wiki/Special:BookSources/9780080549996 "Special:BookSources/9780080549996") . Retrieved 19 November 2016. "Despite the myriad of complications associated with heat illness, an elevation of core temperature above 41.0 °C (often referred to as fever or hyperpyrexia) is the most widely recognized symptom of this syndrome." 8. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kar2008_8-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kar2008_8-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kar2008_8-2) Hutchison, James S.; et al. (June 2008). ["Hypothermia therapy after traumatic brain injury in children"](https://doi.org/10.1056%2FNEJMoa0706930). New England Journal of Medicine. 358* (23): 2447–2456\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1056/NEJMoa0706930](https://doi.org/10.1056%2FNEJMoa0706930). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18525042](https://pubmed.ncbi.nlm.nih.gov/18525042). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [46833](https://api.semanticscholar.org/CorpusID:46833). "We hypothesized that, as compared with normothermia (36.5 to 37.5°C), treatment with hypothermia..." 9. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-pmid_37669046_9-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-pmid_37669046_9-1) Ley, C; Heath, F; Hastie, T; Gao, Z; Protsiv, M; Parsonnet, J (5 September 2023). ["Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10481327). JAMA Internal Medicine. 183* (10): 1128–1135\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1001/jamainternmed.2023.4291](https://doi.org/10.1001%2Fjamainternmed.2023.4291). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [10481327](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10481327). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [37669046](https://pubmed.ncbi.nlm.nih.gov/37669046). 10. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-10) Weintraub, Karen (April 2020). ["Are Human Body Temperatures Cooling Down?"](https://www.scientificamerican.com/article/are-human-body-temperatures-cooling-down/). Scientific American. Retrieved 10 March 2022. 11. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly_11-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly_11-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly_11-2) Kelly, Greg S. (March 2007). ["Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease"](https://web.archive.org/web/20170809134435/http://altmedrev.com/publications/12/1/49.pdf) (PDF). Alternative Medicine Review. 12* (1): 49–62\. [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [17397267](https://pubmed.ncbi.nlm.nih.gov/17397267). Archived from [the original](http://www.altmedrev.com/publications/12/1/49.pdf) (PDF) on 2017-08-09. Retrieved 2016-12-28. 12. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Mac_12-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Mac_12-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Mac_12-2) Mackowiak, Philip A.; Wasserman, Steven S.; Levine, Myron M. (1992-09-23). "A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich". Journal of the American Medical Association. 268* (12): 1578–1580\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1001/jama.1992.03490120092034](https://doi.org/10.1001%2Fjama.1992.03490120092034). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [1302471](https://pubmed.ncbi.nlm.nih.gov/1302471). 13. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-13) Del Bene, Victor E. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.), ["Temperature"](https://www.ncbi.nlm.nih.gov/books/NBK331/), Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.), Boston: Butterworths, [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-409-90077-4](https://en.wikipedia.org/wiki/Special:BookSources/978-0-409-90077-4 "Special:BookSources/978-0-409-90077-4") , [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [21250173](https://pubmed.ncbi.nlm.nih.gov/21250173), retrieved 2023-02-15 `{{citation}}`: CS1 maint: work parameter with ISBN ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN "Category:CS1 maint: work parameter with ISBN")) 14. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SundLevander2002_14-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SundLevander2002_14-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SundLevander2002_14-2) Sund-Levander, Märtha; Forsberg, Christina; Wahren, Lis Karen (2002). "Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review". Scandinavian Journal of Caring Sciences. 16* (2): 122–8\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1046/j.1471-6712.2002.00069.x](https://doi.org/10.1046%2Fj.1471-6712.2002.00069.x). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [12000664](https://pubmed.ncbi.nlm.nih.gov/12000664). 15. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-2) [d](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-3) [e](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-4) [f](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-5) [g](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-6) [h](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-7) [i](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-8) [j](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Longo_15-9) Longo, Dan L., ed. (2011). [Harrison's principles of internal medicine](https://web.archive.org/web/20120429231736/http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4) (18th ed.). New York: McGraw-Hill. p. 142. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-07-174889-6](https://en.wikipedia.org/wiki/Special:BookSources/978-0-07-174889-6 "Special:BookSources/978-0-07-174889-6") . Archived from [the original](http://accessmedicine.com/resourceTOC.aspx?resourceID=4) on 2012-04-29. Retrieved 2012-03-16. 16. ^ [a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly1_16-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly1_16-1) [c](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Kelly1_16-2) Kelly, Greg S. (December 2006). ["Body temperature variability (Part 1): a review of the history of body temperature and its variability due to site selection, biological rhythms, fitness, and aging"](https://web.archive.org/web/20170808231722/http://altmedrev.com/publications/11/4/278.pdf) (PDF). Alternative Medicine Review. 11* (4): 278–93\. [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [17176167](https://pubmed.ncbi.nlm.nih.gov/17176167). Archived from [the original](http://www.altmedrev.com/publications/11/4/278.pdf) (PDF) on 2017-08-08. Retrieved 2016-12-28. 17. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Atkinson_17-0) Atkinson, G.; Coldwells, A.; Reilly, T.; Waterhouse, J. (January 1993). "A comparison of circadian rhythms in work performance between physically active and inactive subjects". Ergonomics. 36 (1–3\): 273–281\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1080/00140139308967882](https://doi.org/10.1080%2F00140139308967882). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [8440222](https://pubmed.ncbi.nlm.nih.gov/8440222). 18. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-18) Katz, Brigit (16 January 2020). ["Human Body Temperature Is Getting Cooler, Study Finds"](https://www.smithsonianmag.com/smart-news/human-body-temperature-getting-cooler-study-finds-180974006/). [Smithsonian](https://en.wikipedia.org/wiki/Smithsonian_\(magazine\) "Smithsonian (magazine)"). Retrieved 22 January 2020. 19. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-19) Protsiv, Myroslava; Ley, Catherine; Lankester, Joanna; Hastie, Trevor; [Parsonnet, Julie](https://en.wikipedia.org/wiki/Julie_Parsonnet "Julie Parsonnet") (2020-01-07). Jit, Mark; Franco, Eduardo; Waalen, Jill; Rühli, Frank (eds.). ["Decreasing human body temperature in the United States since the Industrial Revolution"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946399). eLife. 9 e49555. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.7554/eLife.49555](https://doi.org/10.7554%2FeLife.49555). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [2050-084X](https://search.worldcat.org/issn/2050-084X). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [6946399](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946399). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [31908267](https://pubmed.ncbi.nlm.nih.gov/31908267). 20. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Elert2005_20-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Elert2005_20-1) Wong, Lena (1997). Elert, Glenn (ed.). ["Temperature of a healthy human (body temperature)"](https://hypertextbook.com/facts/1997/LenaWong.shtml). The Physics Factbook. Retrieved 2022-01-25. 21. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-21)* Newman, B. H.; Martin, C. A. (October 2001). ["The effect of hot beverages, cold beverages, and chewing gum on oral temperature"](https://doi.org/10.1046%2Fj.1537-2995.2001.41101241.x). Transfusion. 41 (10): 1241–1243\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1046/j.1537-2995.2001.41101241.x](https://doi.org/10.1046%2Fj.1537-2995.2001.41101241.x). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [0041-1132](https://search.worldcat.org/issn/0041-1132). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [11606822](https://pubmed.ncbi.nlm.nih.gov/11606822). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [24681501](https://api.semanticscholar.org/CorpusID:24681501). 22. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-22) Kiekkas, P; Stefanopoulos, N; Bakalis, N; Kefaliakos, A; Karanikolas, M (April 2016). "Agreement of infrared temporal artery thermometry with other thermometry methods in adults: systematic review". Journal of Clinical Nursing. 25 (7–8\): 894–905\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1111/jocn.13117](https://doi.org/10.1111%2Fjocn.13117). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [26994990](https://pubmed.ncbi.nlm.nih.gov/26994990). 23. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-23) Zhen, C; Xia, Z; Long, L; Pu, Y (October 2014). "Accuracy of infrared ear thermometry in children: a meta-analysis and systematic review". Clinical Pediatrics. 53 (12): 1158–65\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1177/0009922814536774](https://doi.org/10.1177%2F0009922814536774). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [24879119](https://pubmed.ncbi.nlm.nih.gov/24879119). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [24982111](https://api.semanticscholar.org/CorpusID:24982111). 24. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-24) Paprocki, Jonathan (2012-12-18). ["Sleep deprivation disrupts regulation of body heat"](https://sleepeducation.org/sleep-deprivation-disrupts-regulation-body-heat/). Sleep Education. Retrieved 2023-02-15. 25. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-25) Lack, Leon C.; Gradisar, Michael; Van Someren, Eus J. W.; Wright, Helen R.; Lushington, Kurt (August 2008). "The relationship between insomnia and body temperatures". Sleep Medicine Reviews. 12 (4): 307–317\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.smrv.2008.02.003](https://doi.org/10.1016%2Fj.smrv.2008.02.003). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [1087-0792](https://search.worldcat.org/issn/1087-0792). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18603220](https://pubmed.ncbi.nlm.nih.gov/18603220). 26. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-26) ["Define Afebrile"](https://www.dictionary.com/browse/afebrile). 27. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Dodd_27-0) Dodd, Susanna R.; Lancaster, Gillian A.; Craig, Jean V.; Smyth, Rosalind L.; Williamson, Paula R. (April 2006). "In a systematic review, infrared ear thermometry for fever diagnosis in children finds poor sensitivity". Journal of Clinical Epidemiology. 59 (4): 354–7\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.jclinepi.2005.10.004](https://doi.org/10.1016%2Fj.jclinepi.2005.10.004). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [16549256](https://pubmed.ncbi.nlm.nih.gov/16549256). 28. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-SciDirect_28-0) McKenzie, Jack E.; Osgood, David W. (2004). "Validation of a new telemetric core temperature monitor". Journal of Thermal Biology. 29 (7–8\): 605. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_\(identifier\) "Bibcode (identifier)"):[2004JTBio..29..605M](https://ui.adsabs.harvard.edu/abs/2004JTBio..29..605M). [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.jtherbio.2004.08.020](https://doi.org/10.1016%2Fj.jtherbio.2004.08.020). 29. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-29) Nidermann, Reto; Wyss, Eva; Annaheim, Simon; Psikuta, Agnes; Davey, Sarah; Rossi, René Michel (January 2014). ["Prediction of Human Core Body Temperature Using Non-Invasive Measurement Methods"](https://www.dora.lib4ri.ch/empa/islandora/object/empa%3A6081). International Journal of Biometeorology. 58 (1): 7–15\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_\(identifier\) "Bibcode (identifier)"):[2014IJBm...58....7N](https://ui.adsabs.harvard.edu/abs/2014IJBm...58....7N). [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1007/s00484-013-0687-2](https://doi.org/10.1007%2Fs00484-013-0687-2). [hdl](https://en.wikipedia.org/wiki/Hdl_\(identifier\) "Hdl (identifier)"):[20\.500.11850/80468](https://hdl.handle.net/20.500.11850%2F80468). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [23760405](https://pubmed.ncbi.nlm.nih.gov/23760405). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [11772946](https://api.semanticscholar.org/CorpusID:11772946). 30. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-30) Mendt, Stefan; Maggioni, Martina Ana; Nordine, Michael; Steinach, Mathias; Opatz, Oliver; Belavy, Daniel; Felsenberg, Dieter; Koch, Joachim; Shang, Peng; Hanns-Christian, Gunga; Stahn, Alexander (2017). "Circadian Rhythms in Bed Rest: Monitoring Core Body Temperature via Heat-Flux Approach Is Superior to Skin Surface Temperature". Chronobiology International. 34 (5): 666–676\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1080/07420528.2016.1224241](https://doi.org/10.1080%2F07420528.2016.1224241). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [27726448](https://pubmed.ncbi.nlm.nih.gov/27726448). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [205581198](https://api.semanticscholar.org/CorpusID:205581198). 31. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-31) Uth, Marc-Florian; Koch, Jochim; Sattler, Frank (2016). ["Body Core Temperature Sensing: Challenges and New Sensor Technologies"](https://doi.org/10.1016%2Fj.proeng.2016.11.154). Procedia Engineering. 168: 89–92\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.proeng.2016.11.154](https://doi.org/10.1016%2Fj.proeng.2016.11.154). 32. ^ [*a](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-0) [b](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-Bazett_Love_Newton_Eisenberg_1948_pp._3%E2%80%9319_32-1) Bazett, H. C.; Love, L.; Newton, M.; Eisenberg, L.; Day, R.; Forster, R. (1948). "Temperature Changes in Blood Flowing in Arteries and Veins in Man". Journal of Applied Physiology. 1* (1): 3–19\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1152/jappl.1948.1.1.3](https://doi.org/10.1152%2Fjappl.1948.1.1.3). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [8750-7587](https://search.worldcat.org/issn/8750-7587). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [18887571](https://pubmed.ncbi.nlm.nih.gov/18887571). 33. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-33) Chudler, Eric H. ["Biological Rhythms"](http://faculty.washington.edu/chudler/clock.html), Neuroscience for Kids, faculty.washington.edu 34. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-34) [temperature registered more than 115.7"](https://news.google.com/newspapers?id=y4IwAAAAIBAJ&sjid=t0QDAAAAIBAJ&pg=4281,2822445&dq=115.7+degrees&hl=en), Bulletin Journal, August 7, 1980 35. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-35) ["2-latek z Polski rekordzistą. Przeżył wychłodzenie poniżej 12 st. C."](https://dzienniknaukowy.pl/zdrowie/2-latek-z-polski-rekordzista-przezyl-wychlodzenie-ponizej-12-st-c) Dziennik Naukowy (in Polish). 5 December 2014. Retrieved 23 September 2022. 36. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-36) Mroczek, T.; Gladki, M.; Skalski, J. (26 June 2020). ["Successful resuscitation from accidental hypothermia of 11.8°C: where is the lower bound for human beings?"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886275). European Journal of Cardio-Thoracic Surgery. 58 (5): 1091–1092\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1093/ejcts/ezaa159](https://doi.org/10.1093%2Fejcts%2Fezaa159). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [7886275](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886275). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [33084865](https://pubmed.ncbi.nlm.nih.gov/33084865). 37. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-37) Tomita, K., et al. "Examination of factors affecting the intraoral perception of object size: A preliminary study." Journal of oral rehabilitation 44.4 (2017): 237–243. 38. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-38) Al-Tubaikh, Jarrah Ali. "Infectious Diseases and Tropical Medicine." Internal Medicine. Springer, Cham, 2017. 441–493. 39. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-vecellio_39-0) Vecellio, Daniel J.; Wolf, S. Tony; Cottle, Rachel M.; Kenney, W. Larry (2022-02-01). ["Evaluating the 35°C wet-bulb temperature adaptability threshold for young, healthy subjects (PSU HEAT Project)"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8799385). Journal of Applied Physiology. 132 (2): 340–345\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1152/japplphysiol.00738.2021](https://doi.org/10.1152%2Fjapplphysiol.00738.2021). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [8750-7587](https://search.worldcat.org/issn/8750-7587). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [8799385](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8799385). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [34913738](https://pubmed.ncbi.nlm.nih.gov/34913738). 40. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-timperley_40-0) Timperley, Jocelyn (31 July 2022). ["Why you need to worry about the 'wet-bulb temperature'"](https://www.theguardian.com/science/2022/jul/31/why-you-need-to-worry-about-the-wet-bulb-temperature). The Guardian. 41. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-41) [Inwit Publishing, Inc. and Inwit, LLC – Writings, Links and Software Demonstrations – A Fahrenheit–Celsius Activity](https://web.archive.org/web/20110713052807/http://www.inwit.com/inwit/writings/fahrenheitcelsiusactivity.html), inwit.com 42. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-42) [Oxford Dictionary of English](https://en.wikipedia.org/wiki/Oxford_Dictionary_of_English "Oxford Dictionary of English"), 2010 edition, entry on "blood heat" 43. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-43) [Collins English Dictionary](https://en.wikipedia.org/wiki/Collins_English_Dictionary "Collins English Dictionary"), 1979 edition, entry on ["blood heat"](https://www.collinsdictionary.com/us/dictionary/english/blood-heat) 44. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-44) Wunderlich, Carl Reinhold August (1868). [Das Verhalten der Eigenwärme in Krankheiten](https://archive.org/details/dasverhaltender00wundgoog) \[The behavior of the self-warmth in diseases\]. Leipzig: O. Wigand. ; its 1871 2nd edition translated into English and published with the title [On the temperature in diseases: a manual of medical thermometry](https://archive.org/details/ontemperaturein01wundgoog). 45. [^](https://en.wikipedia.org/wiki/Human_body_temperature#cite_ref-45) Fischetti, Mark (2018), "Graphic Science: Goodbye, 98.6", Scientific American, vol. 319, no. 6 (December)
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