Summer takes many of us outdoors to enjoy our favorite past times. The summer sun is not only hot, it can burn and burns can lead to skin cancer.

Marta Van Beek, MD, a dermatologist at University of Iowa Hospitals and Clinics, says any sun that you're exposed to without proper protection can be a problem. "People often think you have to have a burn before you actually receive sun damage. Any amount of sun exposure that results in a tan can cause sun damage at the cellular level in your skin.

"If you can't avoid outside activities during the peak sun hours, which are between 10 a.m. and 2 p.m., I have three other recommendations for you:

• Seek shade when possible when you're outdoors
• Wear protective clothing, such as a wide-brimmed hat and long sleeves
• Wear sunscreen

"I recommend patients wear sunscreen everyday, whether they believe they're going to go outside or not. I recommend SPF 30, mostly because generally people don't put enough sunscreen on to achieve the SPF that's on the bottle. Patients use about half of what is really recommended for the amount of sunscreen. So when you use an SPF of 30, you're actually getting probably an SPF of 15," she says.

Sunscreen formulas have greatly improved over the last several years, but don't rely on any sunscreen to really last all day. "Sunscreen and its ability to protect you depends on your level of activity.

• Are you sweating a lot?
• Are you exercising?
• Is there friction on your skin?
• Have you been in the water?

"All of these things remove sunscreen and prevent it from protecting you to its full potential," she says. "So regardless of what the bottle says, I recommend that patients reapply after every one to two hours.

If you stayed in the sun too long and now have a sunburn, Van Beek suggests protective care. "You can take a pain reliever like Ibuprofen or Tylenol for the pain. Warm water or tepid baths sometimes, or slightly cool water, can actually relieve some of the pain.

"Moisturization is very important when you have a sun burn. We recommend that patients use a good moisturizer, without any fragrance or plant extract. Aloe is a plant extract and when your skin is inflamed, it's not that uncommon to develop an allergy or an allergic reaction to the plant extracts in lotions and creams. So one with very little additives, preservatives, or plant extract, something like Vaseline Petroleum Jelly, is probably best," she says.

"We get concerned when people have large areas of blisters, when you're loosing large sheets of skin. Often when people lose such large pieces of skin, they can actually have difficulty trying to keep their fluid balance, and that's the time when maybe they should seek medical attention.

"Skin damage happens with very little sun exposure. You can have skin damage even before you get a sun burn. Even the amount of sun that it takes to achieve a tan results in some cellular damage of the skin. So both acute exposure, such as sun burn, and chronic exposure, which results in a tan, damages cells and DNA which is what causes, eventually, abnormal cells to divide, which is actually skin cancer.

"I think sunscreen is an absolute must for the cyclists involved in RAGBRAI. People need to apply it to every exposed surface area of skin before they get on the bike, and repeat it every time they stop either to get a drink or take a break, especially during these hot days where there's going to be a lot of perspiration. And if they wear a hat and as much protective clothing as possible, that will also help the situation," says Van Beek.

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