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Excessive exposure to the sun can cause sunburn, skin cancers, wrinkles and premature aging of the skin. And these days, unprotected skin can suffer ill effects of ultraviolet (UV) rays regardless of the weather. The jury is still out, but many experts believe that the breakdown of the Earth's protective layer has contributed, at least in part, to a ten-fold rise in melanoma, the most serious form of skin cancer, in the last 50 years. Beware of Ultraviolet Light In the early days of tanning research, it was discovered that if you could block out a certain kind of ultra violet light, known as UVB, you could delay or prevent sunburn. Another type of ultraviolet light (different wave lengths), called UVA was found to be just as effective as UVB at stimulating melanin production (tanning), but it took a lot more of it to burn you. Early sun protection products were formulated to "block out the sun's harmful burning rays (UVB) while letting in the beneficial tanning rays (UVA)." We now know that UVA is just as carcinogenic (cancer-causing) and just as physically damaging as UVB, but this is a recent discovery. This explains why the SPF numbers (sun protection factor) refer to only one kind of ultra-violet light (UVB). And why one product can give you much greater protection than another, even if they both have the same SPF number. They may protect equally well against UVB but unequally against UVA. |
What The SPF Number Means An SPF of 8 means you can be exposed to UVB radiation 8 times as long as you could without it before burning. In determining SPF values, the FDA uses a standard amount that turns out to be just about twice the amount the average person on the beach uses. So to get an idea of how much protection you're really getting, start by dividing the SPF in half. Choosing a sunscreen with an SPF of at least 15 is usually a safe bet for UVB protection. Since swimming, sweating and contact can further reduce protection, reapplying these products every two hours is highly recommended. Most clothing offers at least some sun protection, the darker and the tighter the weave, the better. A white nylon jacket has an SPF of about 4, while a new blue denim has an SPF of 1000. Blocking UVA The white stuff you see on peoples' noses and lips at the beach is either titanium dioxide or zinc oxide, both of which effectively block both kinds of UV light. Products containing dibenzoylmethanes offer the fullest protection against ultraviolet radiation. The bottom line is that exposure to the sun can have harmful effects. If you must go out, protect yourself with an appropriate sunscreen. One of your best sources of information on sun-blocking preparations is your Valu-Rite pharmacist. He or she can help you find the products best suited to your needs. |