It was about two hundred years ago that scientists figured out that the average body temperature for a healthy adult was 98.6F or 37C. We have all been taught that number from kindergarten on and it one of those constants that we all know and on which we base actions in our real life. However, according to an article in Science News:
“A 2017 study among 35,000 adults in the United Kingdom found average body temperature to be lower (97.9°F), and a 2019 study showed that the normal body temperature in Americans (those in Palo Alto, California, anyway) is about 97.5°F.”
Another group of scientists who have spent almost two decades studying the Tsimane, an indigenous population of forager-horticulturists in the Bolivian Amazon found a cooling over a short period of time:
“In the 16 years since [Michael] Gurven, co-director of the Tsimane Health and Life History Project, and fellow researchers have been studying the population, they have observed a rapid decline in average body temperature — 0.09°F per year, such that today Tsimane body temperatures are roughly 97.7°F.”
There is no definitive reason yet understood for these changes. However, some researchers believe that a fall in the number of infections due to modern hygiene is one possibility. Another is that air conditioning in the summer and heating in the winter has reduced the body’s need to compensate for external temperatures.
I just think it is cool we are getting cooler!