Normal Temperature
- Definitions of “normal” continue to remain contested.
- 700 temperature readings from 148 volunteers were studied.
- Mean oral temperature: 98.20 F (370 C)
- An upper limit of normal as 98.90 F (37.20 C) in the morning and 99.90 F (37.70 C) overall.
- Noted differences in men and women
- “When modern thermometers are used to monitor oral temperatures in young or middle-aged adults, fever is most appropriately defined as an early morning temperature of 37.20 C (990 F) or greater or an evening temperature of 37.80 C (1000 F) or greater.
Mackowiak, P., et. al. A critical appraisal of 98.60, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich, JAMA. 1992;268:1579-1580
- The rectal temperature is about 10 F (0.550 C) higher than the oral temperature.
- With tachypnea, the difference averages 0.930 C (1.670 F), increasing with respiratory rate.
- Patients should refrain from eating, drinking or smoking for at least 15 minutes prior to an oral temperature measurement.
Axillary temperatures, done properly: lie still, keep arm tight, and wait exactly 10 minutes
2026 Research:
Independent researcher Matthew Cormier explores what falling body temperature could tell us about immune defenses, metabolic health and the rise of chronic illness in his second Journal of Independent Medicine paper.
For generations, 98.6°F has been the number we reach for to decide whether a body is behaving normally. It no longer describes us. Long-term records show that average human body temperature has fallen nearly a full degree since the 1800s, to about 97.7°F today.
Over the same stretch, chronic illness became common. The paper cites estimates that 40–50% of U.S. children now meet criteria for at least one chronic condition, with comparable trends in adolescents and young adults. The leading explanation in the scientific literature treats the cooling as harmless, a byproduct of cleaner living and fewer lifelong infections.
In his second paper for the Journal of Independent Medicine, following his 2025 review of viral reactivation and autism, independent researcher Matthew Cormier asks whether it is a warning light instead. Reviewing 48 published studies, he argues that body temperature is a readout of the two systems that keep us alive, our metabolism and our immune defenses, and that a population growing colder may be losing ground on both.