A RUNNER’S relationship with the sun is complicated. You love soaking up its warmth and energy, especially after a winter of too many frigid or treadmill-based kilometres. But you hate when it leaves its mark – age spots, unflattering tan lines, painful burns – and you dread the long-term damage that may result.
It’s a given that there are serious reasons to be wary, especially if you’re logging epic summer kilometres. But you might be surprised to learn that running in the sun also does your body good. Here’s how to balance the risks and rewards.
Bad News for Skin…
The sun’s damaging ultraviolet rays can cause skin cancer, as everyone knows. And runners may be especially vulnerable. An Archives of Dermatology study found that marathoners showed increased numbers of abnormal moles and age spots, putting them at higher risk for malignant melanoma. Training outdoors increases runners’ exposure, but researchers cited another less obvious contributing factor: Long-term intense exercise (like marathon training) can suppress the immune system, increasing vulnerability to skin damage.
Adding insult to injury, when your immunity is suppressed, you are also more susceptible to other nonthreatening (but still annoying) skin issues like blisters and chafing. “Overexposure to UV radiation can suppress your skin’s ability to properly protect itself and heal,” says Elizabeth K. Hale, M.D., a clinical associate professor of dermatology at the New York University School of Medicine who is also a marathoner.
What’s more, UV rays can contribute to eye damage, such as cataracts, and up to 90 percent of the visible signs of skin aging, such as age spots and wrinkles, according to the United States Environmental Protection Agency.
…but Good News for Health
Soak all that information in, and you may think you should never venture out on a sunny day. But from a biological standpoint, it’s absolutely vital to your mental and physical health. “Being in the sun is part of a healthy physiology,” says Martin Feelisch, Ph.D., a professor of experimental medicine and integrative biology at the University of Southampton in England.
Case in point: vitamin D, which your body churns out when your skin is exposed to UVB rays. More than three quarters of the U.S. population is deficient in the sunshine vitamin, which is associated with depression, bone fractures, hypertension, autoimmune diseases, and cancer–and a lack of sun exposure is the biggest reason why levels are low, according to research published in The American Journal of Clinical Nutrition.
But that’s not the only role the sun plays in our health. Recent research from Edinburgh University in the U.K. reports that the skin houses large amounts of nitric oxide, a compound that dilates blood vessels to reduce blood pressure and lower the risk of heart attack and stroke. Sunlight activates those nitric oxide supplies and releases them into circulation, says Richard Weller, M.D., a senior lecturer in dermatology who conducted the research.
Combine the health benefits of vitamin D and nitric oxide, and it’s easy to see why one long-term study of the entire Danish population over the age of 40 found that people who had been diagnosed with skin cancer were less likely to suffer from a heart attack or hip fracture or die from any cause – period. That’s no endorsement for skin cancer, of course, but it might be one for the sun.
And here’s the kicker: Spending time in the sun may lead to faster race times, according to new research presented at the American College of Sports Medicine conference in May. After cyclists spent 20 minutes under a UVA lamp, they completed a 16km time trial faster than when they did it without the rays, says Chris Easton, Ph.D., an exercise physiologist at the University of the West of Scotland. “The large stores of nitric oxide released from the skin help more blood and oxygen flow to your muscles,” says Easton. “Plus, by reducing the amount of oxygen the muscles use to produce force, the nitric oxide helps you go harder, longer.” (The cyclists’ times were even faster than when they ate rhubarb and swiss chard, which also increase circulating levels of nitric oxide, but to a lesser degree than the sun.)
Play it Safe
“Get out, but don’t get burned,” Feelisch says. Even if you run when the sun appears closer to the horizon (before 10 a.m. and after 4 p.m.) and wear sunscreen, you will still get a fair amount of sun exposure–and its benefits, says Ashish C. Bhatia, M.D., assistant professor of clinical dermatology at the Northwestern University Feinberg School of Medicine. While sunscreen lowers your body’s production of vitamin D, your body will still produce a decent supply of the vitamin, according to a study conducted at King’s College London’s St. John’s Institute of Dermatology. And while studies haven’t yet examined sunblock’s effects on nitric oxide levels, Feelisch says you’ll likely enjoy some of the benefit even if you apply sunblock.
Increasing your immunological defenses can also help safeguard your skin from damage. Schedule rest and recovery time each week, get at least eight hours of sleep each night, and fuel up on antioxidants. “Focus on eating a well-balanced diet that is very colorful,” Dr. Hale says. “The more colors, the wider the array of damage-fighting antioxidants you’re getting.”
No matter how careful you are, check your body for new or changing moles every month, and visit your dermatologist once a year or more (depending on your personal risk factor) for a skin-cancer screening. When looking for a dermatologist, ask if they have a specialty in sports dermatology, recommends marathoner Brian B. Adams, M.D., professor and interim chair of dermatology and director of the Sports Dermatology Clinic at the University of Cincinnati College of Medicine. After all, you’ll benefit from a doc who understands your lifestyle and will work with it, rather than just telling you to stick to the treadmill.