- Sunscreen Myths—Busted!. Women's Health/ June 2009 issue.

Myth: Dark skin doesn't burn, so you don't need sunscreen 

Reality: "All complexions can burn," says Karyn Grossman, M.D., a dermatologist in Santa Monica and New York City. "A dark-skinned African-American doesn't need as high an SPF as a pale redhead, since she has more melanin in her skin for natural protection." Still, that extra melanin doesn't guard against the UV damage that accelerates aging or causes cancer. If you have dark skin, you need a broad-spectrum sunscreen with an SPF of 15 or higher.

Myth: The sun gives you great highlights
Reality: "Sun exposure damages your hair too," says Katie Rodan, M.D., of Stanford University. In fact, those highlights are evidence of damage that can give your hair a dry, strawlike texture and cause breakage. Keep your hair healthy by using UV-shielding products. Try Barex Sun Essential Oil ($27, beautyhabit.com). 



Myth: Getting a tan zaps zits

Reality: A tan can temporarily camouflage the redness of a pimple and dry out the skin's surface, but sun exposure will eventually lead to more breakouts. "It causes a buildup of dead skin cells that clogs pores," Rodan says. "This actually worsens acne." The sun also dehydrates the skin; when that happens, your oil glands try to compensate by pumping out more oil, which may leave you with more zits.

Myth: There's no benefit to an SPF higher than 30
Reality: A higher number is slightly better. "You get 99 percent sunburn protection with SPF 90, versus 96 percent with SPF 30," says Howard Sobel, M.D., of Lenox Hill Hospital in New York City. Over a lifetime, a few more percentage points of protection can add up to a lot less sun damage.

- Why You Should Run. Women's Health/ June 2009 issue.

RUNNING AND INJURY PREVENTION
Dedicated road ­runners, listen up: You've probably had to defend your sport a thousand times against this persistent myth, so take note: Running will not wreck your hips and blow out your knees.

According to a research ­review in the Journal of Anatomy, running does not increase your risk of osteoarthritis, the ­decay of cartilage that causes joint pain and inflammation.

In fact, many researchers even propose that the strong muscles you develop putting in all those miles could actually help guard against osteoarthritis.

Exercise will definitely help you avoid one ­important risk factor for the disease in women: obesity.

- The Truth About Birth Control And Weight Gain. Women's Health/ June 2009 issue.

Birth control really can cause weight gain, the American Journal of Obstetrics and Gynecology reports.

The worst offender is Depo-Provera, the contraceptive shot. Depo contains a synthetic hormone that keeps estrogen levels low, preventing the release of eggs.

Women who used it were twice as likely as those who used nonhormonal contraceptives to become obese over three years, even after accounting for exercise and eating habits.

Here's how to beat the creep:
Method:
Depo-Provera

Average weight gain over 3 years:
11.26 lb

Average percentage ­increase in body fat:
3.41

Fight the flab:
If your diet and exercise habits stay the same after starting and you gain a lot, talk to your doc about other methods.

Method
The Pill

Average weight gain over 3 years:
3.2 lb

Average percentage ­increase in body fat:
1.63

Fight the flab:
Women who strength-trained for at least two hours a week lost less calorie-burning muscle mass.