Keeping Your Skin Safe

Some people assume that if they wear sunscreen, they can sit for hours in th esun to et tan. There is no such thing as a safe tan, says Dr. Alan Kling, a board-certified dermatologist who treats people with skin cancer.

"A tan by definition means that your skin is damaged. Your body is increasing the amount of pigment it produces as a way to fight against the sun's damaging rays," he says.

Even on cloudy days, he says, people should wear sunscreen.

"The sun's harmful rays go through clouds. In fact, some people get more serious burns on cloudy days than they do on sunny days," he says. On sunny days when the temperature is hotter, people tend to spend less time directly in the sun; on cloudy days when the heat is not as intense, they spend more time outside, Dr. Kling explains.

All sunscreens are sold with different SPFs - sun protection factors. The following is Dr. Kling's definition of SPF: "SPF is a measure of how long you can stay exposed to the sun without burning. For instance, if you begin to tan or burn after 10 minutes, an SPF of 15 extends your protection 15 times longer," he says.

Here are Dr. Kling's explanations of four different sunscreens and the differences:

How often to reapply it?

"For your average person, once every two hours," the doctor says. "If you are sweating, about one hour to one and a half hours," he says.

There are also fabrics that offer better protection from the sun than others. The following are just a few with comments by Dr. Kling:

• Tightly Woven Fabric - The tighter the fabric, the harder it is for the sun's rays to reach you. A tee shirt for instance when it's dry offers an SPF of 7; a polo shirt about 9.
• Synthetic Fibers - These are good because they tend to have tighter weaves.
• Dark Fabric - Dark fabric absorbs the light better, though you will feel hotter in dark clothing.