For nearly 150 years, 98.6 degrees Fahrenheit has been the accepted standard temperature for the human body. But at least two dozen modern studies have concluded the number is too high.
In a new study, researchers from Stanford University argue that Wunderlich’s number was correct at the time but is no longer accurate because the human body has changed.
Today, they say, the average normal human-body temperature is closer to 97.5 degrees Fahrenheit.
“That would be a huge drop for a population,” said Philip Mackowiak, emeritus professor of medicine at the University of Maryland School of Medicine and editor of the book “Fever: Basic Mechanisms and Management.”
Body temperature is a crude proxy for metabolic rate, and if it has fallen, it could offer a clue about other physiological changes that have occurred over time.
“People are taller, fatter and live longer, and we don’t really understand why all those things have happened,” said Julie Parsonnet, who specializes in infectious diseases at Stanford and is senior author of the paper. “Temperature is linked to all those things. The question is which is driving the others.”