Stanford researchers have determined that average human body temperature in the United States has decreased since the 1800s
Since the 19th century, the average human body temperature in the United States has dropped, according to researchers at the Stanford University School of Medicine.
“Our temperature’s not what people think it is,” said Julie Parsonnet, MD, professor of medicine and of health research and policy. “What everybody grew up learning, which is that our normal temperature is 98.6, is wrong.”
That standard of 98.6 degrees Fahrenheit was established by German physician Carl Reinhold August Wunderlich in 1851. Modern studies, however, have called that number into question, suggesting that it’s too high. A recent study, for example, found the average temperature of 25,000 British patients to be 97.9 F.
In a study published today in eLife, Parsonnet and her colleagues explore body temperature trends and conclude that temperature changes since the time of Wunderlich reflect a true historical pattern, rather than measurement errors or biases. Parsonnet, who holds the George DeForest Barnett Professorship, is the senior author. Myroslava Protsiv, a former Stanford research scientist who is now at the Karolinska Institute, is the lead author.
The researchers propose that the decrease in body temperature is the result of changes in our environment over the past 200 years, which have in turn driven physiological changes.