“Normal” Human Temperature May Be Lower When Baseline Inflammation Is Lower

When I was a child my mother would hand me an oral thermometer to take my temperature and often the temperature would come out below 98.6 degrees. She would be annoyed and hand it back to me, saying that I should put it in right this time. I would painfully jab the thermometer back under my tongue, discouraged that I would never figure out what I was doing wrong. So several decades later, I smiled when I read the commentary quoted below. (Hey mom, maybe I was doing it OK all along.)

(p. A2) Nearly 150 years ago, a German physician analyzed a million temperatures from 25,000 patients and concluded that normal human-body temperature is 98.6 degrees Fahrenheit.

That standard has been published in numerous medical texts and helped generations of parents judge the gravity of a child’s illness.

But at least two dozen modern studies have concluded the number is too high.

The findings have prompted speculation that the pioneering analysis published in 1869 by Carl Reinhold August Wunderlich was flawed.

Or was it?

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.

. . .

“Wunderlich did a brilliant job,” Dr. Parsonnet said, “but people who walked into his office had tuberculosis, they had dysentery, they had bone infections that had festered their entire lives, they were exposed to infectious diseases we’ve never seen.”

For his study, he did try to measure the temperatures of healthy people, she said, but even so, life expectancy at the time was 38 years, and chronic infections such as gum disease and syphilis afflicted large portions of the population. Dr. Parsonnet suspects inflammation caused by those and other persistent maladies explains the temperature documented by Wunderlich and that a population-level change in inflammation is the most plausible explanation for a decrease in temperature.

For the full commentary, see:

Jo Craven McGinty. “THE NUMBERS; 98.6 Degrees Is No Longer the Body’s Norm.” The Wall Street Journal (Saturday, January 18, 2020): A2.

(Note: ellipsis added.)

(Note: the online version of the commentary has the date January 17, 2020, and has the title “THE NUMBERS; 98.6 Degrees Fahrenheit Isn’t the Average Anymore.”)

One thought on ““Normal” Human Temperature May Be Lower When Baseline Inflammation Is Lower”

  1. Just wondering about the amazing coincidence: was the average ever precisely 98.6 degrees F, i.e. precisely 37 degrees C, or did Wunderlich merely round the Celsius number off because the data were noisy, as they surely must have been under conditions that long ago, to end up with exactly 37 degrees? (Note: this doesn’t necessarily contradict the thesis that the baseline has shifted. But how much?)

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