A Tiktok doctor went viral for claiming that running gives you a 'gaunt, old face.' Here's why that's not true.

• Dr. Gerald Imber went viral on TikTok for saying long-distance running causes premature aging.
• Some worry that "runner's face" is caused by repeated movement reducing skin elasticity.

"Runner's face" — the idea that running frequently can give you saggy cheeks and a gaunt visage due to skin losing elasticity — has been a controversial topic of concern among athletes online for years. There are even purported facial exercises out there that promise to keep your cheeks plump, no matter how much you jog every week.

Now, a new viral TikTok video from a plastic surgeon has riled people up once again, by claiming that long-distance running apparently makes you age faster.

"I have a pet peeve," Dr. Gerald Imber, a plastic surgeon practicing in New York, started off. "Half my patients love me for it, and half my patients hate me for it." Apparently, the doctor dislikes the effects of running on the skin.

While Imber said running a few miles a few times a week is fine (without really specifying what he means by "a few"), his main gripe with consistent running is that it supposedly accelerates aging and is guaranteed to give you a "gaunt, old face."

TikTokers were predictably split: Many commenters joked about this newfound reason not to exercise, while others (usually runners) found the advice insulting.

But while Dr. Ivy Lee, a dermatologist practicing in Los Angeles, said she's had patients complain about runner's face, "there is no scientific evidence to support or refute this claim," she told Insider.

Though runners can experience some changes to their faces, she said the explanations are a lot more obvious — and potentially fixable — than quitting your favorite workout.

Running can cause natural weight loss in our face

Lee's first theory of why faces can look more hollowed out from running is that overall weight loss may look more drastic on our faces.

According to Lee, people who exercise lose weight all over their bodies, including a reduction of fat in their facial pads. Like "Ozempic face," where semaglutide users can quickly lose cheek fat, dramatic weight loss can change our face shape — but it doesn't mean our skin is losing elasticity.

Prolonged sun exposure can speed up signs of aging

More than anything else, Lee said "chronic sun exposure" from any intense outdoor exercise can cause premature aging such as wrinkles and dark spots.

Additionally, she said prolonged exercise usually results in sweating, meaning you should reapply sunscreen, "which is hard to do when you are running long distances."

To mitigate sun damage, some runners wear hats or long sleeves in addition to sunscreen.

While running can pose risks to some people, such as stress fractures or other injuries, the benefits include improved cardiovascular health, sleep, and mental health, all of which can lengthen your life.

Maybe lifelong outdoor running can lead to a few more fine lines or sun spots. But for all the positive perks it adds to your life, most runners would need a more pressing reason to stop.