Are you running a fever? 98.6°F may no longer be the baseline

For seemingly forever, we’ve been told 98.6 degrees Fahrenheit is the standard for a normal body temperature. However, recent studies suggest that the number may be outdated.

According to research, the average body temperature has dropped to around 97.9°F, with variations based on age, health conditions and even race and gender. The discussion gained traction recently when a viral TikTok video questioned whether 99.1°F should count as a fever.

It turns out, they have a point.

A history lesson on 98.6°F

The idea that 98.6°F is “normal” comes from 19th-century German physician Carl Reinhold August Wunderlich, who took more than a million temperature readings and set the standard. But that was nearly 200 years ago, and our bodies — and the world — have changed.

“We are not the same people that we were in the middle of the 19th century,” Dr. Julie Parsonnet, the George DeForest Professor of Medicine and a public health researcher at Stanford Medicine, told USA Today.

Harvard study finds new ‘normal’

A 2017 Harvard Medical School study analyzed data from more than 35,000 patients and found the average body temperature is 97.9°F, ranging from 97.2°F to 98.4°F.

The study also found body temperature varies by age, gender and medical conditions. Older adults tend to run cooler, African American women the warmest, and older white men the coolest. People with hypothyroidism often have lower temperatures, while those with cancer or higher BMIs tend to run warmer.

Why we may be running cooler

The decline in body temperature is most likely linked to improvements in health and lifestyle, according to a 2020 study published in the open-access journal eLife.

In the 19th century, people faced more infections, harsh living conditions, and limited medical care, which kept their immune systems constantly active — raising their internal temperatures. Thanks to modern medicine, our bodies no longer have to work as hard to fight off disease, allowing temperatures to drop slightly.

“Physiologically, we’re just different from what we were in the past,” Parsonnet said in a press release, the Atlanta Journal-Constitution previously reported. “The environment that we’re living in has changed, including the temperature in our homes, our contact with microorganisms and the food that we have access to.”

So, what’s considered a fever?

Doctors traditionally define a fever as 100.4°F or higher. But if your normal temperature is lower, even 99.1°F might make you feel unwell. Instead of focusing on one number, experts recommend tuning into your body’s norm.

Here’s what to do if you start feeling feverish, according to WebMD.

Hydrate: Dehydration makes everything worse, so drink plenty of fluids.

Rest: Give your body time to recover, even if your temp isn’t considered very high.

Monitor symptoms: Fever is just one clue. Watch for chills, aches and fatigue.

Call a doctor if symptoms worsen: If you feel terrible despite a “normal” temp, don’t ignore it.

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