To sun, or not to sun?

McClatchy Newspapers (MCT) - You ditched the baby oil with iodine ions ago, but you still have some burning questions about less-obvious sun no-no's. Now that spring is here and everyone's exposure time is likely to increase, get updated on the latest sun sense:

_Tanning beds: Safer than sun? No. Exposure to ultraviolet radiation damages your skin whether the exposure comes from tanning beds or natural sunlight. This damage increases the risk of skin cancer and premature skin aging. In fact, most tanning beds emit mainly UVA rays _ which may increase the risk of melanoma, the deadliest form of skin cancer, says the Mayo Clinic. If you want the golden glow of a tan, consider using a sunless tanning lotion or spray.

_Does sunscreen expire? Sunscreens are designed to remain at original strength for up to three years. This means you can use leftover sunscreen from one summer to the next.

_What sunglasses offer the best protection? UV radiation from the sun can damage not only the skin of your eyelids, but also the clear outer parts of the eye _ the cornea and conjunctiva. UV exposure also contributes to the development of certain types of cataracts. Choose sunglasses that block at least 99 percent of UVB rays and at least 95 percent of UVA rays, according to the American National Standards Institute. Skip sunglasses that are labeled "cosmetic" or don't offer details on UV protection.

_In sunscreens, is SPF 70 better than SPF 30? The issue of how high the SPF, or sun-protection factor, goes remains a subject of ongoing debate. Here is what we know: SPF is based on how long your skin can stay in the sun without burning compared with unprotected skin. So someone whose skin starts to redden after five minutes on the beach would get 75 minutes of skin protection from an SPF 15 sunscreen and 150 minutes of protection from an SPF 30. A sunscreen with an SPF of 30 blocks 97 percent of the sun's burning rays, compared with 93 percent blocked by sunscreens with an SPF of 15.

Although a higher SPF sunscreen, if used properly, should allow you to stay in the sun that much longer without burning, it isn't clear if high SPF sunscreens block any more than 97 percent of burning rays. "Block" is a misleading term because no product you can see through will block 100 percent of the sun from your skin. The American Academy of Dermatology recommends using at least a 15 SPF, reapplied every two hours, after swimming or sweating.

_More info: The current regulation of sunscreen labeling leaves a lot to be desired. The FDA is expected to weigh in with new rules, particularly for UVA claims. Meanwhile, there's a helpful analysis of different products, including a lot of safety info, from the Environmental Working Group at www.cosmeticsdatabase.com/splash.

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© 2009, The Miami Herald.