*Flashback Friday*

°*This post originally appeared on The PediaBlog on January 28, 2020.

 

Is 98.6 °F Still “Normal”?

 

 

Normal body temperature is 98.6°F (37°C). Alice Park explains how we came to accept that number — way back in 1871:

That number was determined by a German physician, based on millions of readings from 25,000 German patients, taken by sticking thermometers under their arms. When doctors in the U.S. and Europe repeated the experiment in local populations, they came up with the same number, so it stuck.

 

Stanford University researchers analyzed data that was collected during the Civil War in 1862 until 2017. Park says humans are cooling off as the years and decades go by, suggesting that “the standards that doctors have been using to define normal temperature and fever might need to be reworked”:

The team found that average body temperatures in the earliest database, from the Union Army veterans, were higher than the temperatures recorded in each of the latter two periods. On average, the temperatures dropped by 0.03°C and 0.029°C per decade for men and women, respectively, over the 150-year span […] Within the Union Army population, for example, the trend remained strong; temperatures were higher among those born earlier than among those born later, by about 0.02°C per decade.

 

Using these numbers, if normal body temperature was 98.6°F in 1862, today it would be closer to 97.8°F (36.5°C). It all makes sense to the lead author of the study:

It makes sense that body temperatures would change over time, says Parsonnet. “We have grown in height on average, which changes our temperature, and we have gotten heavier, which also changes our body temperature,” she says. “[Today,] we have better nutrition, better medical care, and better public health. We have air conditioning and heating, so we live more comfortable lives at a consistent 68°F to 72°F in our homes, so it’s not a struggle to keep the body warm. It’s not beyond the imagination that our body temperatures would change as a result.”

 

There are more reasons that explain why doctors might now consider a lower body temperature the new normal:

Perhaps the most important factor, however, is the development of treatments for infectious diseases over the last century. “We have gotten rid of many of the inflammatory conditions that people had—tuberculosis, syphilis, periodontal disease, wounds that didn’t heal, dysentery, diarrhea—with antibiotics and vaccines,” says Parsonnet. “Plus, we conquered general inflammation with non-steroidal anti-inflammatory drugs and statins, all of which enable us to live almost inflammation-free.” That, in turn, might have contributed to a creeping decline in average body temperature as the body is freed from heating up to fight off disease.

 

Practically speaking, doctors tend to consider a range of temperatures when deciding whether the number on the thermometer is normal or abnormal. This range, of course, is always open to interpretation:

99.9 Fahrenheit degrees
Stable now, with rising possibilities
It could be normal but it isn’t quite
Could make you want to stay awake at night

— 99.9 F° by Suzanne Vega

 

(Google Images)

 

source http://www.thepediablog.com/2022/01/28/flashback-friday-191/