When Sean Hosmer, 22, began working as a lifeguard at Rocky Neck State Park in East Lyme, Conn., four years ago, the solar social standards were quite different.
"When I first started, there was this big race to get a tan," he says. "Now people are more careful."
Even so, the Rocky Neck lifeguards are not exactly skin-protection experts. Mr. Hosmer says they start out with a sunscreen with a Sun Protection Factor of 15 (not strong enough for fair-skinned folks standing nearly naked in the sun for six or more hours) and, over the summer, they work down to an SPF 4 (not strong enough, period).
For the light-skinned, there is no such thing as a healthy tan. A tan is your skin scrambling to save itself as best it can from an overdose of the sun's ultraviolet radiation. Exposure to invisible ultraviolet rays stimulates the production of the skin's pigment -- melanin. This is tanning.
Baking out in the sun to tan "is the worst thing you can do," says Dr. Marti Rothe, a dermatologist at the University of Connecticut Health Center in Farmington.
The problem is that the people who want tans -- white or light-skinned people -- do not tan easily. Dr. Caron Grin-Jorgensen, another health center dermatologist, says for those people, the issue of whether those people, the issue of whether or not a tan is "protective" is moot because getting there is what does the damage. While you are soaking in rays, you are causing mutations in the pigment cells themselves - cellular changes that may lead to skin cancer.
Those who do not want to tan -- dark- or black-skinned people -- are naturally highly resistant to the sun's UV radiation. They have and produce lots of melanin. For those people, production of more melanin in response to sun exposure is protective, according to Dr. Madhu A. Pathak, a research dermatologist at Harvard University Medical School. (However, the American Academy of Dermatology urges Americans of every skin shade to protect themselves from too much sun.)
While skin cancer is rare among dark-skinned people, it is rising sharply among light-skinned Americans, and sun exposure is the main culprit. Final figures have not been computed, but the New York-based Skin Cancer Foundation estimates that more than 600,000 new cases of skin cancer were diagnosed in 1991 and that 8,500 Americans died of the disease last year.
Depletion of the Earth's protective ozone layer is making sun exposure more troublesome, because thinning ozone lets more UV radiation hit the Earth's surface. Last year, the U.S. Environmental Protection Agency estimated ozone loss could create 12 million additional skin cancer cases among Americans alive today or born before 2030.
The sun's damage is cumulative. Today's light-skinned adults probably got too much sun as children, so they need to be careful from now on. Because most people get most of their sun exposure before age 18, protecting children and adolescents is crucial.
One way to avoid the sun is to stay indoors, but that is no fun. Wide-brimmed hats and long-sleeve shirts and pants help, but it is tough to wind-surf in slacks. So we must rely on sunscreens and sun blocks: products with SPF numbers of 15 or higher.
SPF numbers are calculated on something dermatologists call the minimal erythema dose, or MED, which is the amount of sun exposure you need in one day to get a slight sunburn (erythema).
If you multiply the SPF number by the amount of time it takes you to get a slight burn, you get a rough idea how long the same burn will take after you have applied the sunscreen.
Dr. Pathak says there are almost too many factors to produce an average MED as measured in time-in-the-sun: season, time of day, altitude, geography and surroundings. But he says 20 minutes -- unprotected at noon, in midsummer, in the northern United States -- is a rough MED for fair-skined, blue-eyed types.
Multiply the Sun Protection Factor number on your sunscreen (let's say 15) by your MED time (20 minutes), and you get five hours. So 20 minutes unprotected gives you the same burn you'd get in five hours with an SPF 15 sunscreen (so you would have to spend less than five hours in the sun to avoid the burn).
You can see why dermatologists encourage everyone to use a sunscreen with an SPF of 15 or higher. Some suggest light-skinned individuals start with SPF 30 -- it doubles the amount of sun exposure they can safely receive. The U.S. Food and Drug Administration is expected to come out with new proposed regulations involving sunscreen later this year that will, among other things, encourage fair-skinned Americans to use products with SPFs higher than 15.
But SPF isn't everything. Some of the chemicals that block the sun's rays may not agree with your skin. Dermatologists recommend sunscreen not be used on children younger than 6 months -- their skin is especially permeable. Newborns should be kept out of the sun.