To many people, summer means hanging out at the pool or the beach, soaking up rays in pursuit of a golden tan. But before you put on your bathing suit and head to the pool (or pay for a bed or booth in a tanning salon), there are a few things to think about when it comes to your skin and sun exposure.

How Tanning Happens

The sun's rays contain two types of ultraviolet radiation that reach your skin: UVA and UVB. UVB radiation burns the upper layers of skin (the epidermis), causing sunburns.

UVA radiation is what makes people tan. UVA rays penetrate to the lower layers of the epidermis, where they trigger cells called melanocytes (pronounced: mel-AN-oh-sites) to produce melanin. Melanin is the brown pigment that causes tanning.

Melanin is the body's way of protecting skin from burning. Darker-skinned people tan more deeply than lighter-skinned people because their melanocytes produce more melanin. But just because a person doesn't burn does not mean that he or she is also protected against skin cancer and other problems.

Tanning Downsides

UVA rays may make you tan, but they can also cause serious damage. That's because UVA rays penetrate deeper into the skin than UVB rays. UVA rays can go all the way through the skin's protective epidermis to the dermis, where blood vessels and nerves are found.

Because of this, UVA rays may damage a person's immune system, making it harder to fight off diseases and leading to illnesses like melanoma, the most serious type of skin cancer. Melanoma can kill. If it's not found and treated, it can quickly spread from the skin to the body's other organs.

Skin cancer is epidemic in the United States, with more than 1 million new cases diagnosed every year. Although the numbers of new cases of many other types of cancer are falling or leveling off, the number of new melanoma cases is growing.

In the past, melanoma mostly affected people in their fifties or older, but today dermatologists see patients in their twenties and even late teens with this type of cancer. Experts believe this is partly due to an increase in the use of tanning beds and sun lamps, which have high levels of UVA rays. Getting a sunburn or intense sun exposure may also increase a person's chances of developing this deadly cancer.

Exposure to UVB rays also increases your risk of getting two other types of skin cancer: basal and squamous cell carcinoma.

The main treatment for skin cancers is cutting the tumors out. Since many basal or squamous cell carcinomas are on the face and neck, surgery to remove them can leave people with facial scars. The scars from surgery to remove melanomas can be anywhere on the body, and they're often large.

Cancer isn't the only problem associated with UV exposure. UVA damage is the main factor in premature skin aging. To get a good idea of how sunlight affects the skin, look at your parents' skin and see how different it is from yours. Much of that is due to sun exposure, not the age difference!

UV rays can also lead to another problem we associate with old people: the eye problem cataracts.

Sun Smarts

Staying out of the sun altogether may seem like the only logical answer. But who wants to live like a hermit? The key is to enjoy the sun sensibly, finding a balance between sun protection and those great summer activities like beach volleyball and swimming.

Sunscreens block or change the effect of the sun's harmful rays. They're one of your best defenses against sun damage because they protect you without interfering with your comfort and activity levels.

The SPF number on a sunscreen shows the level of UVB protection it gives. Sunscreens with a higher SPF number provide more defense against the sun's damaging UV rays.

Here are some tips to enjoy the great outdoors while protecting your skin and eyes from sun damage:

• Wear sunscreen with an SPF of at least 30 every day, even on cloudy days and when you don't plan on spending much time outdoors. Wearing sunscreen every day is essential because as much as 80% of sun exposure is incidental — the type you get from walking your dog or eating lunch outside. If you don't want to wear a pure sunscreen, try a moisturizer with sunscreen in it, but make sure you put on enough.
• Use a broad-spectrum sunscreen that blocks both UVA and UVB rays. Ideally, it should also be hypoallergenic and noncomedogenic so it doesn't cause a rash or clog your pores.
• Reapply sunscreen every 1½ to 2 hours. If you're not sure you're putting on enough, switch to sunscreen with a higher SPF, like SPF 30. No matter what the SPF, the sun can break down the UVA ingredients in sunscreen. Even if you don't get a sunburn, UVA rays could still be doing unseen damage to your skin.
• Reapply sunscreen after swimming or sweating.
• Take frequent breaks. The sun's rays are strongest between 10:00 A.M. and 4:00 P.M. During those hours, take breaks to cool off indoors or in the shade for a while before heading out again.
• Wear a hat with a brim and sunglasses that provide almost 100% protection against ultraviolet radiation.

Other things to know when it comes to avoiding sun damage:

• You probably know that water is a major reflector of UV radiation — but so are sand, concrete, and even snow. Snow skiing and other winter activities carry significant risk of sunburn, so always apply sunblock before hitting the slopes.
• Certain medications, such as antibiotics used to treat acne and birth control pills, can increase your sun sensitivity (as well as your sensitivity to tanning beds). Ask your doctor whether your medications might have this effect and what you should do.
• Avoid tanning "accelerators" or tanning pills that claim to speed up the body's production of melanin or darken the skin. There's no proof that they work and they aren't approved by government agencies for tanning purposes.

Trauma-free Tans

Even when you're serious about protecting your skin, you may sometimes want the glow of a tan. Luckily, many products on the market — but not sun lamps or tanning beds — will let you tan safely and sun-free.

One safe way to go bronze is with sunless self-tanners. These "tans in a bottle" contain dihydroxyacetone (DHA), which gradually stains the dead cells in your skin's outer layer. The "tan" lasts until these skin cells slough off, so exfoliating or vigorously washing will make the color fade faster. Typically, self-tanners last from several days to a week.

You may have to try a few brands of self-tanner to find one that looks best with your skin tone. For a subtle, goof-proof glow, try moisturizers that contain a modest amount of fake tanner, letting you gradually build up a little color without blotches and staining — or the smell that some people dislike. All of these options are cheap, too, usually around $10.

Ask a friend to help you apply self-tanner to spots you can't reach, like your back. And be sure to wash your hands as soon as you finish applying the tanner. Areas of your body that don't normally tan (like the palms of your hands or soles of the feet) just look dirty if you leave tanner on them.

With self-tanners, you get better results if you exfoliate your skin with a scrub brush or loofah before the tanner is applied. This evens your skin tone and removes dead skin cells.

If you use a sunless tanner, you'll need to wear plenty of sunscreen when you go outdoors to protect you from the sun's rays. Self-tanners don't generate melanin production, so they won't protect you against sunburn (and some scientists believe they might even make skin more susceptible to sun damage).

If you're thinking about using a sunless tanner, it's a good idea to avoid airbrush or spray-on tans. The FDA hasn’t approved DHA for use internally or on mucous membranes (like the lips). Spray tans may have unknown health risks because people can breathe in the spray, or the tanner may end up on their lips or eye area.