MAY 3, 2011.
The Joy of Researching the Health Benefits of Sex .
By MELINDA BECK.
Is sex good for your health—or is that just a fantasy?
Many studies suggest that sex is as good for your health as vitamin D and broccoli. It not only relieves stress, improves sleep and burns calories; it can also reduce pain, ease depression, strengthen blood vessels, boost the immune system and lower the risk of prostate and breast cancer.
Yet, does sex make people healthier or do healthier people have more sex?
Some benefits of sex—beyond producing a baby, that is—are obvious even without scientific evidence. "When you have good sex, there's a relaxation response and…you lie there and life is great," says Dr. Goldstein, who is also the director of sexual medicine at Alvarado Hospital in San Diego, Calif.
Much of that is due to chemistry—the rush of hormones and neurotransmitters that rise and fall during sexual activity. Sex boosts dopamine, which activates the brain's centers of desire and reward "just like chocolate and winning at gambling," says Erick Janssen, a senior scientist at the Kinsey Institute at Indiana University.
Sex also increases oxytocin which reduces fear and stimulates endorphins, the body's natural painkillers, which is why sex can bring temporary relief from back pain, migraines and other body aches.
Dopamine levels fall after orgasm, and levels of prolactin rise, bringing on feelings of satisfaction and sleepiness, particularly in men. "That's the nice, relaxed feeling afterwards," says Stuart Brody, a psychologist at the University of the West of Scotland who has conducted numerous studies on sex and health. Of course, timing isn't always perfect. In a 2006 survey of 10,000 British men, 48% admitted to having fallen asleep during sex.
Sex is also seen as good exercise—but the effect is actually modest. Although couples obviously differ, sex generally burns an estimated five calories per minute, or roughly 50 to 150 calories total.
Sex does increase heart rate and blood pressure—as high as 125 beats per minute and to 160 peak systolic rate—about as much as walking up two of stairs. And several studies suggest that having it regularly can protect against cardiovascular problems. One British study found that men who reported having three or more orgasms per week experienced 50% fewer heart attacks than those who engaged less frequently—perhaps because orgasm triggers the release of the hormone DHEA (dehydroepiandrosterone), which helps with circulation and arterial dilation.
Frequent sex may benefit men's health another way: by boosting testosterone, which in turn is linked to stronger muscles, more energy and better cognition. (Sex's effect on testosterone was shown in a now-famous article in Nature in 1970. A man stranded on a remote island with no women saw his beard stop growing. Then it resumed when he returned to civilization and sex again.)
Sex also improves women's moods—although how it does is controversial. One 2002 study of 293 college women at the State University of New York in Albany found that those who engaged in unprotected sex were less likely to be depressed than those whose partners use condoms or who don't have sex at all. The researchers noted that semen contains testosterone, estrogen, prolactin and prostaglandins, which can pass through vaginal walls into the bloodstream and elevate mood.
Some of the most intriguing findings suggest that frequent sex can lower the risk of some types of cancer. A 2004 study of 29,000 male health professionals in the Journal of the American Medical Association found that those who reported having the most frequent ejaculations—21 or more a month—had a much lower risk of prostate cancer than those reporting four to seven per month.
Several studies also suggest that having sex extends life in general. A study in the British Medical Journal found that men who had sex less than once per month were twice as likely to die in the next 10 years than those who had sex once per week. A 25-year study of 270 men and women aged 60 to 96 conducted at Duke University found that the more men had sex, the longer they lived. Women who said they enjoyed their sex lives lived seven to eight years longer than those who were indifferent. But factors such as intelligence, health and activities also played a role in living longer, too.