There are two types of ultraviolet radiation, UVA and UVB. Both damage the skin and can cause skin cancer. SPF (Sun Protection Factor) is a measure of a sunscreen’s ability to prevent UVB from damaging the skin.
If it takes 20 minutes for your unprotected skin to start turning red, using an SPF 15 sunscreen theoretically prevents reddening 15 times longer or about five hours. To be safe, however, only use broad-spectrum sunscreens to protect the skin from both UVA and UVB rays. Recent Food and Drug Administration regulations require sunscreens that protect against all types of sun-induced skin damage to be labeled “Broad Spectrum” and “SPF 15” (or higher), which will protect against sunburn and can reduce the risk of skin cancer and early skin aging. Any sunscreen not labeled as “Broad Spectrum” or that has an SPF value between 2 and 14, can only help prevent sunburn. Here are some other tips on sunscreen:
. Apply sunscreen about 30 minutes before going out in the sun.
. Reapply the same amount of sunscreen every two hours.
. Reapply immediately after swimming, toweling off, or sweating a lot.