To Get a Healthy Tan, You Gotta Do the Math


Buying sunscreen for the beach, once as simple as filling the cooler with ice, today poses an obstacle course of lifestyle decisions:

Cream? Lotion? Regular? Oil-free? Under makeup? In makeup? Sweat-resistant? Sports-dry? Fragrance-free? Herbal medicinal? Waterproof? Hypoallergenic? Infrared fighter? Super SPF?

“This market proliferation is a good sign,” says Peter Heinlein, chemist and project leader at Consumers Union, publisher of Consumer Reports magazine. “It means that people are becoming conscious that being tan doesn’t mean you are healthy.”

Most sunscreens halt or slow burning and wrinkling by blocking the UVA rays, which cause tanning and burning, and the UVB rays, which damage collagen that gives skin elasticity, from the sun’s ultraviolet spectrum.


And although there are still questions about the extent of protection against skin cancer, “there is no point in cooking yourself,” said Heinlein. His team tested more than 25 popular sunscreens, with various protection claims, priced from 99 cents an ounce to $1.51 an ounce. “Most of them lived up to their billing.”

A sunscreen’s protection against UVB is gauged by its SPF or sun protection factor (commonly 15 or 30, though a few brands have an SPF of up to 50).

To calculate effectiveness, multiply the SPF times the minutes you can stay in the sun unprotected before you start to burn. If it is 40 minutes, an SPF 15 sunscreen extends the protection 15 times as long--up to 10 hours.

It’s skin type, not age, that determines the SPF needed, says Heinlein, and a rule of thumb is: The lower the skin type, the higher the SPF.


“Dark-skinned people have a greater tolerance for the sun,” Heinlein said. “Skin-type classifications range from a chalk-white-skinned redhead at Type 1, who always burns, to an equatorial African at Type 6.”

In between are Type 2, people who burn easily and tan minimally; Type 3, people who sometimes burn and gradually tan; Type 4, those who experience minimum burning and always tan; and Type 5, those who very seldom burn and always tan.

Heinlein’s basic advice is to use at least a 15 SPF and follow these rules:

* Don’t put sunscreen on a baby younger than 6 months old because the skin can absorb the active ingredients. Instead, keep the baby under a beach umbrella.

* Be aware that bright surfaces such as sand, concrete and water can reflect sun’s rays onto skin.

* Don’t be stingy. Use 1 ounce (that’s the size of a bartender’s shot glass) per application, repeated after each swim.

* Don’t forget your ears and the tops of your feet.

* Avoid the midday sun (10 a.m. to 3 p.m.), which is most intense.