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The Average Human Body Temperature Is No Longer 98.6 F
We’re all chilling out, new research shows
One of the most widely accepted standard measurements of the human body, a normal temperature of 98.6 degrees Fahrenheit, has declined gradually for more than 150 years in the United States by about 1.6% since the pre-industrial era, a new study published in the journal eLife finds. The cooling off owes largely to improvements in health and medicine and in part to increasingly cushy lifestyles, the study’s researchers think.
Many health practitioners are still using the old, inaccurate number of 98.6 F as the presumed norm, which was set by a German physician in 1851.
“Our temperature’s not what people think it is,” says Dr. Julie Parsonnet, a professor of medicine and health research at Stanford University School of Medicine and the senior author of the study. “What everybody grew up learning, which is that our normal temperature is 98.6, is wrong.”
Parsonnet and her colleagues say many health practitioners are still using the old, inaccurate number of 98.6 F as the presumed norm, which was set by a German physician in 1851 based on 25,000 patients in one city.
The researchers of the new study analyzed three sets of medical records that included body temperature measurements: from 1862 to 1930 on 23,710 veterans of the Civil War; from 1971 to 1975 on 15,301 people from the National Health and Nutrition Examination Survey; and from 2007 to 2017 on 150,280 adults who visited Stanford Health Care.
The mean body temperature of men born in the 2000s is 1.06 F lower than men born in the early 1800s, the researchers concluded. Among women born in the 2000s, body temps have fallen 0.58 F compared with women born in the late 1800s.
The new study is not the first to find the accepted norm is no longer accurate. In 2002, a review of studies conducted between 1935 and 1999 found the mean body temperature to be lower than the standard. For women, rectal temperature readings (generally thought to be the most accurate) ranged from 98.2 F to 98.8 F, and in men, it ranged from 98.1 F to 99.5 F. A 2017 study of 35,488 British men…
