Temperature of a Healthy Human (Body Temperature)

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Edited by Glenn Elert -- Written by his students
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Bibliographic Entry Result
(w/surrounding text)
Campbell, Neil A. Biology. 3rd ed. California: Benjamin Cummings, 1987: 790. "… a human can maintain its 'internal pond' at a constant temperature of 37 °C" 37 °C
"Temperature, Body." World Book Encyclopedia. Chicago: Field Enterprises, 1996. "… a healthy, resting adult human being is 98.6 °F (37.0 °C)" 37.0 °C
Simmers, Louise. Diversified Health Occupations. 2nd ed. Canada: Delmar, 1988: 150-151. "… the normal range for body temperature is 97 to 100 degrees fahrenheit or 36.1 to 37.8 degrees celsius" 36.1–37.8 °C
Eisman, Louis. Biology and Human Progress. Englewood Cliffs, NJ: Prentice Hall, 1972: 125. "… fairly constant temperature of 98.6 degrees" 37.0 °C
McGovern, Celeste. "Snatched From an Icy Death." Alberta Report/Western Report. Academic Abstracts: United Western Communications, 1994: 2. "… core body temperature … the normal 37 °C" 37.0 °C

The normal core body temperature of a healthy, resting adult human being is stated to be at 98.6 degrees fahrenheit or 37.0 degrees celsius. Though the body temperature measured on an individual can vary, a healthy human body can maintain a fairly consistent body temperature that is around the mark of 37.0 degrees celsius.

The normal range of human body temperature varies due to an individuals metabolism rate, the higher (faster) it is the higher the normal body temperature or the slower the metabolic rate the lower the normal body temperature. Other factors that might affect the body temperature of an individual may be the time of day or the part of the body in which the temperature is measured at. The body temperature is lower in the morning, due to the rest the body received, and higher at night after a day of muscular activity and after food intake.

Body temperature also varies at different parts of the body. Oral temperatures, which are the most convenient type of temperature measurement, is at 37.0 °C. This is the accepted standard temperature for the normal core body temperature. Axillary temperatures are an external measurement taken in the armpit or between two folds of skin on the body. This is the longest and most inaccurate way of measuring body temperature, the normal temperature falls at 97.6 °F or 36.4 °C. Rectal temperatures are an internal measurement taken in the rectum, which fall at 99.6 °F or 37.6 °C. It is the least time consuming and most accurate type of body temperature measurement, being an internal measurement. But it is definitely, by far, not the most comfortable method to measure the body temperature of an individual.

Lena Wong -- 1997

Bibliographic Entry Result
(w/surrounding text)
Mackowiak, P. A., Wasserman, S. S., and Levine, M. M. 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 (23-30 September 1992): 1578-80. "Our findings conflicted with Wunderlich's in that 36.8 degrees C (98.2 degrees F) rather than 37.0 degrees C (98.6 degrees F) was the mean oral temperature of our subjects …. Thirty-seven degrees centigrade (98.6 degrees F) should be abandoned as a concept relevant to clinical thermometry …." 36.8 °C
"Fever: finding the right temp." Nursing 93. 23 (June 1993): 82. [Abstract Source: FirstSearch. H.W. Wilson. 1997.] "Abstract: A recent study of body temperature in 148 healthy adults revealed that only 8 percent of 700 readings were "normal", i.e., 98.6 °F or 37 °C. In addition, diurnal, sex, and racial differences were observed. It is suggested that a feverish state may not be implied unless the body temperature exceeds 99.9 °F or 37.7 °C." not 37 °C
Mackowiak PA, Worden G. Carl Reinhold August Wunderlich and the evolution of clinical thermometry. Clinical Infectious Diseases. 18, 3 (March 1994): 458-67. [Find this paper! Not just the abstract.] [Find it!]
Cutnell, John D. & Kenneth W. Johnson. Physics. 3rd ed. New York: Wiley, 1995: 392. "What is your normal body temperature? It's probably not 98.6 °F, the oft-quoted average that was determined in the nineteenth century. A recent study has reported an average temperature of 98.2 °F." 36.8 °C
Shoemaker, Allen L. What's Normal? Temperature, Gender, and Heart Rate. Journal of Statistics Education. 4, 2 (1996). "One population mean that students all 'know' is the mean normal body temperature of 98.6 degrees F. What is surprising is that recent medical research has posited that the mean normal temperature is really 98.2 degrees F!" 36.8 °C
[Shoemaker supplies text files consisting of body temperature and heart rate data for 65 men and 65 women. This appears to be Mackowiak's data from the 1992 paper in JAMA. The values reported to the right are the mean values ± the standard deviation.] 98.4±0.7 °F
(36.9±0.4 °C)

98.1±0.7 °F
(36.7±0.4 °C)
Vital Signs. Family Internet [dead website]. Applied Medical Informatics, 1996.
Age Temperature (°F)
0–3 month 99.4
3–6 month 99.5
6 month–1 year 99.7
1–3 year 99.0
3–5 year 98.6
5–9 year 98.3
9–13 year 98.0
> 13 year 97.8–99.1
36.6–37.3 °C
Cox, Paul. Glossary of Mathematical Mistakes [dead website]. 1998. [Citation of: Dewdney, A. K., 200% of Nothing: An Eye Opening Tour Through the Twists and Turns of Math Abuse and Innumeracy. New York: Wiley, 1993.] "For decades it was thought that the normal body temperature was 98.6 °F. This number was calculated from a study in Germany which reported normal at 37 °C. What was not known was that this number was an average rounded to the nearest degree. In other words it was only accurate to two significant digits, not the three we have with 98.6. Scientists today know that normal is actually 98.2 plus or minus 0.6, that is to say anything in the range of 97.6° to 98.8° should be considered normal." 36.4–37.1 °C
Sund-Levander, Märtha; Christina Forsberg and Lis Karin Wahren. Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review. Scandinavian Journal of Caring Sciences. Vol. 16 No. 2 (June 2002): 122. "When summarizing studies with strong or fairly strong evidence the range for oral temperature was 33.2–38.2 °C, rectal: 34.4–37.8 °C, tympanic: 35.4– 37.8 °C and axillary: 35.5–37.0 °C. The range in oral temperature for men and women, respectively, was 35.7–37.7 and 33.2–38.1 °C, in rectal 36.7–37.5 and 36.8–37.1 °C, and in tympanic 35.5–37.5 and 35.7–37.5 °C." [see table below]

I vaguely remember hearing that the oft-quoted healthy human body temperature of 98.6 degrees fahrenheit was a "factoid"-- a statement treated as factual that has, in fact, never been verified. I have sent students out in search of real research on this matter, but they have all come up negative. It is a surprisingly difficult assignment. Source after source faithfully states that the temperature of a healthy human body is 98.6 °F or 37 °C -- no exceptions, end of story. The table above hints at the "truth"of the matter.

The first systematic measurements of human body temperature were performed by the German physician Carl Wunderlich. In 1861 he measured the temperatures of one million healthy individuals (a sample size that seems too large to be believed). The average value was reported as 37 degrees celsius. When converted this value becomes 98.6 degreed fahrenheit. So what's the problem? Wunderlich's value has only two significant figures while the converted value has three. The last digit (the "point six" at the end) should be regarded with great suspicion. Wunderlich's converted value should really be stated as "ninety eight point something" if one is being honest.

In 1992 Mackowiak, Wasserman, and Levine measured the body temperatures of 65 men and 65 women and came up with a value of 36.8 °C (98.2 °F). You can do a statistical analysis of the data yourself. The numbers are available online at numerous websites including The Physics Factbook (see body-temperature.txt).

The findings of Sund-Levander, et al. are summarized in the table below.

  men women overall
oral 35.7–37.7 °C 33.2–38.1 °C 33.2–38.2 °C
rectal 36.7–37.5 °C 36.8–37.1 °C 34.4–37.8 °C
typanic (ear canal) 35.5–37.5 °C 35.7–37.5 °C 35.4–37.8 °C
axillary (armpit)     35.5–37.0 °C

Editor's Supplement -- 1997, 1998, 2005, 2006

Bibliographic Entry Result
(w/surrounding text)
Pontius, Joan. Fahrenheit and Roemer. Metric System -- Just Say No!

Author's quote: "I got this from the Dictionary of Scientific Biography, 1971, the editor in chief was Charles Coulston Gillispie. The entry on Fahrenheit was written by a J. B. Gough."
"When Fahrenheit began producing thermometers of his own, he graduatied [sic] them after what he believed were Roemer's methods. The upper fixed point (labeled 22-1/2 degrees) was determined by placing the bulb of the thermometer in the mouth or armpit of a healthy male. The lower point (labeled 7-1/2 degrees) was determined by an ice and weater [sic] mixture. In addition, Fahrenheit divided each degree into four parts, so that the upper point became 90 degrees and the lower one 30 degrees. Later (in 1717) he moved the upper point to 98 degrees and the lower one to 32 degrees in order to eliminate 'inconvenient and awkward fractions'. (ref- Middleton)" 90 °F

98 °F
"After Fahrenheit's death it became standard practice to graduate Fahrenheit thermometers with the boiling point of water (set at 212 degrees) as the upper fixed point. As a result, normal body tmeperature [sic] became 98.6 dgrees [sic] instead of Fahrenheit's 96 degrees." 96 °F

98.6 °F
Pontius, Joan. Fahrenheit's Thermometer. Metric System -- Just Say No! "Fahrenheit wants to further calibrate his thermometer, but can't figure out how do divide evenly by 7-1/2. He multiplies everything times four. So now body temperature is 90, and ice water is 30, and he can calibrate at 15, 45, and 60 degrees by halving the existing ranges." 90 °F
"Fahrenheit wants to calibrate even more [sic], and realizes that if there were 64 divisions between body temperature and ice water, he could easily and accurately calibrate small divisions. Ice water then becomes 32, and body temperature becomes 96." 96 °F

The information on the webpage cited above is a bit inconsistent (and loaded with spelling errors), but is one of the few with any information on the history of the Fahrenheit temperature scale. Apparently, Fahrenheit modeled his scale after one developed by Römer. He carried over many of Römer's ideas on how the scale should be proportioned, namely the use of body temperature as a fixed point and that all meteorological temperatures should be positive. (Römer and Fahrenheit may have thought that temperatures below 0 °F would not happen.)

The current version of the Fahrenheit scale is, in my opinion, the best temperature scale for meteorology in temperate climates. If you think about it, most air temperatures in the mid latitudes are between 0 °F and 100 °F. It works so well that the average surface air temperature of the earth is very nearly in the middle of this range (something like 50 °F). That makes for a very efficient use of two digits.

Editor's Supplement -- 2000

Bibliographic Entry Result
(w/surrounding text)
Company in brief, Pharmacy Chain 36,6. "We are dedicated to helping our customers lead healthy and long lives. Our name reflects this commitment. 36.6 is the ideal body temperature in Centigrade for healthy adults and children. Pharmacy Chain 36.6 is equally committed to building a healthy, vibrant company which consistently delivers robust returns for our shareholders and employees." 36.6 °C
Наша компания, Аптечная сеть 36,6. "Мы стремимся помогать людям вести здоровый образ жизни, способствовать их долголетию и благополучию. Само название «36,6» говорит о нашем призвании. «36,6» — показатель здоровой температуры тела у детей и взрослых. Для акционеров и для сотрудников Аптечная сеть 36,6 – здоровая и динамичная компания, источник прибыли и благосостояния."
Keith. 98.6 [mp3]. Written by G. Fischoff & T. Powers. 1967. "Hey, ninety eight point six, it's good to have you back again. oh,
Hey, ninety eight point six, her lovin' is the medicine that
saaaved me,
Oh, I love my baaaby"
98.6 °F

Apparently, the unrealistically precise value 36.6 °C has acquired the rank of "ideal body temperature" in Russia. There's even a pharmacy chain named 36,6.

And then there's Keith -- the two hit wonder whose 1967 hit single 98.6 sums up the connection between romance and physical health in a single number.

Editor's Supplement -- 2005

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