|Summer heat is here, so take the necessary precautions to save your skin from sun damage.|
A suntan may look attractive, but skin damage and cancer can leave behind a permanent reminder of summers past. Some simple measures can help save your skin from ultraviolet-light medium waves (UVB), which cause sun burns, and long waves (UVA), which accelerate skin aging.
The best precaution is to monitor when you expose your skin to sun. High-risk times are from 10 a.m. to 3 p.m., as UVB intensity peaks then. When in doubt about the local UV peak, apply this rule of thumb: If your shadow is shorter than your height, be wary of sun exposure.
Also, don’t be fooled by clouds, which may make it appear that the threat from the sun has dissipated. Under the right conditions, UV radiation may in fact increase on shady days over what would be present on a clear day. Water and sand also reflect UV light, increasing risks even in areas that appear shaded.
When you do go outside, make sure to take precautions by covering your skin or using sunblock. The American Academy of Dermatology advises use of a sun protection factor (better known as SPF) of at least 15, and dermatologists prefer formulations of sunblock that block UVA and UVB. The academy’s website has a list of what ingredients block these rays. Some ingredients in some sunblocks can break down after an hour of sun exposure. Some controversy exists as to whether the secondary chemicals formed in the product’s breakdown present a danger. Solid blocks such as zinc or titanium oxide provide the most protection without a chemical breakdown.
Remember that there is a diminishing return in terms of actual UVB blocked with the increase in SPF. An SPF of 2, 15 and 30 will screen 50, 93 and 97 percent of the UVB respectively. An ounce—about one shot glass’ worth—of product is needed to cover typically exposed skin surfaces. Sunblock should be applied 15 to 20 minutes before sun exposure. Any product should be reapplied every two hours and more frequently if the skin becomes wet or if you sweat.
—Brian Svazas, M.D., M.P.H.