Family Vacations, Summer 1996
I f SPF 15 is good, then SPF 30 must be twice as good, right? So why bother with the weak stuff at all, when you could just slather on the high-powered sunscreen and be done with it for the day? Or are the high-SPF screens overkill?
On average, it takes 30 minutes for the skin to redden from the sun (even less time at high altitudes or middle latitudes). An SPF of 2 will double that time to an hour. An SPF of 35 protects 35 times as long, or 17-plus hours (only in the Arctic Circle is the sun even out that long). But high SPFs aren't a rip-off because they protect you against increased UV rays. For every 1,000 feet of elevation gain, four percent more UV radiation is bombarding your skin. (For the mathematically impaired, that means that at 10,000 feet you're absorbing 40 percent more harmful rays than you would at sea level.) Reflection from sand increases UV radiation by 17 percent, while water can reflect an additional 100 percent.
The best rule of thumb is to minimize sun exposure between 10 a.m. and 3 p.m., when the radiation is strongest, and keep infants under six months out of the sun entirely--their skin is especially vulnerable to sunburn. Invest in a sunscreen with an SPF factor of at least 15 (the consensus minimum protection) that will block both UVA and UVB rays. And remember that most
sunscreens take up to 30 minutes to start working. Reapply liberally and frequently; while sunscreens may indeed be waterproof, they're typically toweled off after a swim. Don't forget a lip balm with sunscreen; lips are skin, too. Finally, pack a wide-brimmed hat to prevent scalp-burns.
Copyright 1996, Outside magazine