Reviewed by When a friend spotted a red lump on Georgie Rutherford’s left arm in May 2019, the 34-year-old professional triathlete brushed off her pal’s concern—and forgot it was even there. But during a vacation four months later, Rutherford’s brothers brought up the bump again. Worried it looked “big and angry,” they urged her to seek medical attention.
From the get-go, doctors assured Rutherford it was nothing more than a benign collection of visible blood vessels, so it took several more months for her to finally have the lump biopsied and receive the news: “It was stage 2C melanoma,” she says. “I went numb. How could this have gone from harmless blood vessels to cancer so quickly?”
Meet the experts: Elizabeth Hale, MD, is a clinical associate professor of dermatology at New York University Langone Medical Center. Yehiel Amouyal, is a cosmetic chemist for Bryhel Cosmetic Laboratories. Anthony Rossi, MD, is an assistant attending dermatologist at Memorial Sloan Kettering Cancer Center.
During those months, Rutherford’s melanoma had progressed. And by the time she received her diagnosis in February 2020, doctors said there was a 60 percent chance of her cancer coming back after surgery. It’s a terrifying and all-too-common story: Skin cancer remains the most common cancer in the U.S. and worldwide, and while melanoma (its deadliest form) makes up only 1 percent of those cases, women under the age of 49 are more likely to develop melanoma than any other cancer except for breast and thyroid.
Still, the diagnosis didn’t make sense to Rutherford. Yes, she is fair-skinned with blonde hair, but she had no family history of skin cancer. Plus, she was fit and energetic. “I assumed people with cancer felt sick in some way,” she says.
In light of Rutherford's experience, here's what experts want you to know about the relationship between outdoor exercise and skin cancer, and steps you can take to keep yourself safe.
How Outdoor Workouts May Increase Skin Cancer Risk
Rutherford didn’t feel off—far from it. She’d only just retired from her athletic career at the time of her diagnosis. But, having competed as a triathlete from the ages of 18 to 35—first at the University of Bath in the U.K. and later at the international level—she had often spent six to nine hours a week training outside, more focused on her workouts than on her sun-protection habits.
“I’d put sunscreen on in the summer or at the beach, but not during training,” she says. “I’d use some during long runs or when I was cycling, but I never reapplied or wore it during outdoor swims.”
There’s a good chance those habits contributed to her diagnosis. The data is clear: 90 percent of non-melanoma skin cancers and 86 percent of melanomas are associated with exposure to the sun's ultraviolet radiation, according to The Skin Cancer Foundation (SCF), so protecting your skin when outside, whether by the pool or pounding the pavement, is crucial.
What’s more, the number of people exercising outdoors is increasing (likely a by-product of pandemic-era habits), according to a 2025 report from the Outdoor Foundation, which conducts research on Americans' participation in outdoor activities. In fact, more than 50 percent of women exercise outside, and they spend an average of five hours per week doing so, according to one survey. All this time outdoors, while generally an awesome thing, can potentially have a not-so-great effect on skin: Frequent outdoor exercise was associated with an increased risk of melanoma, according to a 2024 study published in the Journal of Cancer, which concluded that UV exposure was likely to blame.
Skin Cancer Prevention for the Active Woman
That’s not to say you should quit fresh-air workouts—quite the opposite: Staying active may actually help when it comes to cancer risk. After all, those with higher levels of physical activity pre- and post-diagnosis had improved survival outcomes for 11 different types of cancer, research shows. “Many cancers, including melanoma, are immune-mediated,” says Elizabeth Hale, MD, a clinical associate professor of dermatology at New York University Langone Medical Center. “When we’re stressed, immune function suffers, and exercise lowers stress levels, meaning activity can help with a cancer prognosis.”
What all of this definitely tells us is that it’s critical to remain diligent about shielding your skin from UV damage while engaging in outdoor physical activity, says Dr. Hale. Rutherford’s lax SPF habits aren’t unique: Just 29 percent of women and 12 percent of men ages 18 and older applied sunscreen if they were going to be outside for more than an hour, according to data from the Centers for Disease Control and Prevention.
And we get it—prioritizing SPF during outdoor workouts is challenging. You’re likely thinking more about strength and stamina than skin cancer. Plus, applying sunscreen before, much less during, a workout isn’t as simple as, say, slathering it on during the average day. You’ve got water and sweat to contend with, as well as the need to reapply often. But it’s worth the effort to make it more intuitive and less of a pain.
How to Make UV Protection Work for You
First things first: The American Academy of Dermatology recommends people wear a broad-spectrum sunscreen with an SPF of 30 or higher on all areas of exposed skin. Make sure the product you pick is labeled as sweat- or water-resistant to ensure it’ll last for the duration of your workout. (These products are formulated to withstand both water and sweat for up to 40 or 80 minutes since they contain certain ingredients that either help the sunscreen better adhere to skin or create a water-repellent film on its surface, says Yehiel Amouyal, a cosmetic chemist for Bryhel Cosmetic Laboratories.)
And you don't have to just take the brand's word for it: The Food and Drug Administration requires that time claim be tested by applying the sunscreen on a person’s back, then immersing the area in water for 20 minutes, followed by 15 minutes of dry time. The SPF level is tested after two cycles (for a 40-minute claim) or four (for an 80-minute claim).
Still, there’s a huge difference between what happens in a lab and IRL, as well as how much sunscreen will come off if you’re sweating for 80 minutes versus being submerged in water for 80 minutes, says Anthony Rossi, MD, an assistant attending dermatologist at Memorial Sloan Kettering Cancer Center. So if you’re swimming or surfing, it's best to disregard the time claim and reapply anytime you come out of the water. Reapplication is also key on windy days, as aggressive gusts can cause the skin’s outer layer to slough off more easily, exposing skin to more UV rays, according to the SCF. (Opt for thick creams on these days.)
And if it's possible, try to plan your outdoor activity for the early morning or late afternoon to avoid the sun between the hours of 10 a.m. and 2 p.m., which is when the UV index is strongest, says Dr. Hale. (The UV index predicts when ultraviolet radiation will reach its highest levels, using a scale of 1 to 11+.)
Even better, incorporate protective clothing into your arsenal, too. Dr. Hale, who bikes and runs outdoors, says she’s never without a hat, sunglasses, and a long-sleeve UPF (Ultraviolet Protection Factor) top. She also takes oral antioxidants (her fave is the Isdin Sunisdin daily antioxidant supplement) 30 minutes before prolonged periods of sun exposure. Heliocare Daily Use Antioxidant Formula Capsules is another option; research has shown it decreases UV-induced damage. It’s important to note, though, that these pills are not meant to serve as sunscreen substitutes. Think of them as an extra layer of protection.
As Rutherford’s experience makes clear, the importance of reapplication can’t be overstated. Dr. Hale suggests basting your skin in another SPF layer anytime you’re outside for longer than 90 minutes—and sooner if you’re in the water or sweating a lot. Since reapplying on sweaty skin doesn’t feel great, gently pat your slick spots with a towel to remove excess perspiration before adding a fresh coat, says Rossi. Stick products are great on-the-go options because they can be easily stashed in a gym duffel, running vest, or belt bag.
Today, Rutherford, 38, is healthy and cancer-free (her melanoma was surgically removed a month after her diagnosis), though her recovery took several years, complicated by chronic lymphedema caused by the removal of her lymph nodes. The entire experience reshaped her sun-protection strategy. “I thought I was doing a good job wearing sunscreen before this, but I realize now it was very half-hearted,” she says. “These days, I wear SPF year-round and reapply it on my full body, plus I wear a cap and sunglasses and won’t swim without a sleeve on. I want people to know what happened to me, especially those who still think having post-race tan lines is cool.”
Shop Our Favorite Waterproof Sunscreens
The latest water- and sweat-resistant sunscreens feel so great on your skin that you’ll actually want to use them before you hit the road, bike path, tennis court, or waves. Our three favorite go-tos:
Neutrogena Beach Defense Water-Resistant SPF 50+ Sunscreen Stick
It's easy to apply and reapply this sunscreen thanks to its stick format. Plus, it flaunts SPF 50 with water-resistance, so people with active lifestyles really love it—just check the thousands of perfect 5-star ratings on Amazon.
La Roche-Posay Anthelios Kids Gentle Lotion Sunscreen SPF 50
If you need something that'll last through an intense outdoor workout, this should be your go-to since it's water- and sweat-resistant for up to 80 minutes. Plus, it won't irritate sensitive skin.
This sunscreen is specially formulated for active lifestyles and is ideal for outdoor athletes. It has an 80-minute water-resistant time claim, and it won't drip into the eyes or sting. Plus, it is fragrance-free and hypoallergenic.
Styling: Kristen Saladino, Production: Tash Galgut, Hair and Makeup: Madison Levett
First Image Belle You bodysuit,belleyou.com;Aerie shorts, aerie.com for similar styles; Tory Burch sunglasses, saksfifthavenue.com Second Image Vitality jacket, shopvitality.com for similar styles; DKNY sport tank, dkny.com; Cami and Jax bottoms, camiand jax.com Third Image Outdoor Voices top and shorts, outdoorvoices.com for similar styles; Hoka sneakers, hoka.com; Prada sunglasses, nordstrom.com
Melanie Rud is a beauty writer and editor with over 15 years of experience in the industry covering skincare, makeup, hair, and more. Her work has appeared in Shape, Real Simple, Byrdie, In Style, RealSelf, Good Housekeeping, PopSugar, and multiple other print and digital outlets. Additionally, she works as a personal beauty coach and also offers consulting services for beauty companies.
Brian Underwood is beauty director at Women’s Health, where he oversees content strategy for the brand across all platforms, including digital, print, and social. Underwood previously served as beauty and wellness director at Oprah Daily and O, The Oprah Magazine. During his tenure leading beauty content for the Oprah brand at Hearst, stories Underwood commissioned were awarded the Skin Cancer Foundation Media Award and a Fragrance Award for Editorial Excellence (his second). He was the launch Beauty Director of Dr. Oz THE GOOD LIFE, and has held additional editorial positions at Fitness, Organic Style, Good Housekeeping, Life & Style Weekly, and Woman’s Day and has written for Self, Shape, Seventeen, Redbook, Cosmopolitan, and many more. Underwood previously served on the Skin Cancer Foundation’s gala committee and as partnerships director of the Trans Beauty Clinic, a New York-based charitable organization that provided beauty services and workshops to the city’s trans community.
