If you spend more time in the car than you do at the beach, you might still need to slather on the sunscreen, particularly if you do your driving in the daylight.
In a recent study in The Journal of the American Academy of Dermatology, researchers examined the histories of more than 1,000 patients from a local skin cancer clinic. They discovered that those who had spent the most time behind the wheel each week were more prone to developing skin cancers on the left sides of their bodies and faces. (The left side of a driver is exposed to more sunlight.) Seventy-four percent of patients with malignant melanoma -- the deadliest form of skin cancer -- had tumors on their left sides, compared with 26 percent on the right.
Most cars are manufactured with laminated windshields that filter out ultraviolet light. Rear and side windows are usually made of non-laminated glass, which filters out UVB light, the cause of sunburn - but not UVA rays, which penetrate the skin more harmfully.