Do runners need more frequent Botox injections?

Other research has shown that regular running makes you happier (see our fitness director Jen Ator’s Insta for more on how we feel about that). And of course, it's a great cardio workout.

But when it comes to your skin, there are some interesting concerns that runners don’t always think about. So we caught up with dermatologist Robert Anolik, M.D., and Goesel Anson, M.D., plastic surgeon and founder of skin-care brand FIXMD, to talk more about the skin concerns specific to runners.

There’s no doubt that sun is public-enemy number one when it comes to our skin. And while that applies to everyone, it's especially relevant to runners. Think about it: If you're running outdoors for long periods of time, you're getting a lot of extra sun exposure. That means sunburns now, but it could also lead to liver spots, fine lines, and potentially skin cancer down the line. “We know that when we go for a swim, we should be wearing water-resistant sunblock,” explains Anolik. “But we don’t always think about using it when we’re sweating a lot—and it’s exactly what you need.” Look for a mineral stick sunscreen such as the Honest Company SPF 30 Sunscreen Stick, which uses zinc oxide to block the sun's rays.

Your body fat actually plays an important role in regulating your hormones, such as the fertility hormone estrogen. Since some runners tend to have lower levels of body fat, they can sometimes see a decrease in estrogen, which can affect your skin. "As estrogen declines, collagen content decreases, skin becomes thinner, less firm, and more dry," says Anson. Be sure to eat protein-packed foods that will promote collagen production like salmon, lean meats, eggs, and beans, and use a moisturizer packed with hydrating ingredients like hyaluronic acid and collagen-promoting peptides to help your skin stay elastic and supple. (Collagen powder is optional: It won't help your skin's collagen supply, but it may help keep your skin hydrated.)

And note: While running can burn body fat, your body still needs to have a minimum of 10 to 13 percent body fat to function properly. Losing more than that is dangerous, and can cause you to lose your period and affect your body's ability to regulate blood sugar.

Anecdotally, some dermatologists wind up seeing their patients who are runners more frequently for Botox touchups. “I do find that my patients who are in the gym or running every day and have great metabolisms—their Botox wears off a little more quickly,” explains Anolik. He sees it particularly around the eyes or crow’s feet (likely because of squinting). However, there are no studies or data to support this, and not every dermatologist has noticed this effect (it's quite a subject of debate over at RealSelf.com). But if you're concerned, grab a pair of runners’ sunglasses, which can make the squinting effect less noticeable. Plus, it'll protect your eyes from UV rays—a win-win.

However, don't let any of the above risks dissuade you from running. "I think it’s important to remember that physical fitness is much more important than worrying about skin aging variables that are not easily controlled," says Anson. "Rather, focus on the ones you can control easily—taking care of your skin with topical treatments, good nutrition, and avoiding sun and light exposure."