From the February issue of Runner's World

A recent study reports that many runners are low on vitamin D, a nutrient our bodies make by absorbing sunlight. Vitamin D an important nutrient in developing and maintaining strong and healthy bones but another study reports that marathoners show an increased risk for skin cancer. So how should we approach sun protection?

Experts say wear sunscreen (SPF 30 or higher) while running. If you aren’t prone to sunburn, get 10 minutes of midday sun exposure three times a week. If you are, take a multivitamin. “Most daily multivitamins contain 200 to 400 IU of vitamin D,” says dermatologist Barbara A. Gilchrest, M.D. “That’s more than enough for a healthy runner who inevitably gets some sun. Even with a layer of SPF sunscreen, 20 percent of the sun’s UVB rays will enter the skin and produce the maximum daily amount of vitamin D your body needs.”