More sun damage in the snow

Skiers and snowboarders know that the sun can be brutal when it’s reflected off the snow at high altitudes. But just how much ultraviolet radiation bombards them wasn’t known until recently, when 10 fair-skinned ski instructors in Vail, Colo., wore specially designed UV sensors for a month.

Researchers learned that the skiers were exposed to more damaging radiation in a day than they would have been while surfing in Malibu and 10 times more than professional cyclists competing recently in the summertime Tour de Suisse.

The researchers knew that radiation exposure increases about 2% to 3% for every 328 feet of altitude and that reflection from the snow boosts the amount hitting the skin by about 40%. But the digital monitors worn by skiers allowed them to precisely track exposure every five minutes every day in all types of weather.

On average, the skiers received a daily dose of burning UVB rays about 2 1/2 to three times the radiation that would cause a sunburn on the average person. In addition, the average daily exposure to UVA, the rays that penetrate deepest into the skin and lead to premature aging as well as skin cancer, was more than half what it takes to cause significant injury, says Darrell S. Rigel, the lead author of the study and clinical professor of dermatology at New York University.

Since UV damage is cumulative, at those doses skiers can put themselves at a high risk for skin cancer. “In about a third of the days, even in December, when the sun’s rays were weakest, you had enough UV rays to do damage to the skin,” Rigel says. The best protection is an SPF 30 broad-spectrum sunscreen that protects against both UVA and UVB rays, he says.

The study was published in the January issue of the Archives of Dermatology.