Business of Health Care: Body Temperature Decline

Mar 13, 2020


So much of the thinking in medicine has changed over the past 150 years. But there is one number that has remained constant – 98.6 degrees.

That number has represented normal body temperature since German physician Carl Wunderlich first compiled millions of temperature readings from about 25,000 patients in Leipzig in the mid-1800s.

At least until recently.

Researchers from Stanford completed a major study showing that normal human body temperature has been declining since the Industrial Age.

Other recent studies have suggested the same thing, even after adjusting for factors that can have an impact on body temperature.

Researchers believe that there a few different reasons for this – the most important being improvements in medicine and public health.

A fever is a response of the immune system that often indicates the body is fighting off an infection.

Today, there are fewer infectious diseases and harmful bacteria circulating through our bodies when we are well thanks to vaccines, antibiotics, and better sanitation.

That means the body may not need to remain as warm to keep infections at bay like it did 150 years ago.  

More than a fun fact, a lower normal for body temperature has practical implications.

For starters, doctors may need to recalibrate how they calculate when someone has a fever.

But more interestingly, body temperature also serves as a surrogate for our metabolic rate, which is linked to body mass and longevity… meaning it may add a new perspective to conversations about the evolution of human health, weight, and life span.

This report, and other episodes, are available at Business of Health Care is a production of KWBU and Baylor Scott & White Health.