A few days last week, my temperature was 98 or 99 degrees F in the morning — no wonder: I had the flu; my temperature in the evening was 102.5 or 101. On a few days since getting better, my temperature has been 96 or 97 upon getting up in the morning, or within half hour of doing so. I’ve been curious about the 98.6 degree value that is supposedly “normal.” How could it possibly be true for everyone, since it’s only supposed to be an average, and therefore does not account for individual variation? It can’t. An average offered up without a range, a “range of error,” or a standard deviation sets off alarm bells in my head. Here is some information about human body temperature from the Physics Factbook.
“… the normal range for body temperature is 97 to 100 degrees fahrenheit or 36.1 to 37.8 degrees celsius.” From Simmers, Louise. Diversified Health Occupations. 2nd ed. Canada: Delmar, 1988: 150-151. “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. ” From “Fever: finding the right temp.” Nursing 93. 23 (June 1993): 82. [Abstract Source: FirstSearch. H.W. Wilson. 1997.] “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.” From Cox, Paul. Glossary of Mathematical Mistakes. 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.] The average temperature range for women is 98.4±0.7 °F; for men it is 98.1±0.7 °. From Bodytemp.xls, Quantitative Reasoning Center, DePaul University. [See also Mackowiak‘s JAMA article “A critical appraisal of 98.6 degrees F.” –M.G.]On Sizes.com they say about human body temperature:
Persons with heat stroke, a life-threatening condition, have reached temperatures as high as 113° F (44.4°C). Heat stroke is a danger to marathon runners, who may reach temperatures as high as 105.8°F (41°C) and recover–or may continue on to heat stroke. A temperature of 106°F (41.1°C, measured rectally) is a medical emergency; treatment of heat stroke is begun by immediately plunging the patient into an ice-water bath. In children, temperatures of 106°F and above are often accompanied by convulsions. At 108°F, brain damage is common. Temperatures of 114°F (45.6°C) and above are “incompatible with life.”
Hypothermia begins at temperatures below 95°F (35°C). Humans lose consciousness at about 91°F (32.8°C). Severe hypothermia begins when body temperature falls below 86°F (30°C).