All about sex (contd.)

Sex: The Love Limit

Can you max out on sex's body benefits?

Regular sex (and its primary side effect, orgasm) brings serious health benefits: It can cure insomnia, relieve pain, and reduce the risk of cancer, heart disease, depression, Type 2 diabetes, high blood pressure, bladder problems, and more, research suggests. Its power stems mostly from its aerobic element and stress-relieving effects. "You can't be worrying about a problem when you're having an orgasm," points out psychologist Laurie Mintz, author of A Tired Woman's Guide to Passionate Sex.
If sex is a wonder drug, though, few researchers are working out the best dosage—the amount needed for maximum benefit. While large studies examining orgasms' effects on mortality and health frequently find a linear relationship (more sex, better health, period), the research often deems two or more orgasms per week "frequent." Might an upper limit exist, unnoticed at the extreme end of the scale?

One study of 112 couples suggests that moderation is key. Carl Charnetski, a psychologist at Wilkes University in Pennsylvania, found that couples who got it on twice a week had 30 percent higher levels of an important bug-fighting antibody than did less sexually active pairs. But any additional romps—three or four times a week—vitiated the immunity boost. Opioid peptides, which are released during pleasurable experiences, may account for Charnetski's rather befuddling (and, he adds, preliminary) results.
Normally, such peptides strengthen the immune system, but in excess they can act as immunosuppressants. It's unclear whether sex alone could amp up peptides to dangerous levels, but studies suggest a link between an excess of endorphins (an opioid peptide that increases during the deed) and depression, psychosis, and even immobility.
Don't adjust your schedule just yet, however: Men who ejaculate the least (zero to three times a month) and the most (21 or more times a month) have the lowest relative risk for prostate cancer. The groups right in the middle are most likely to develop the disease, according to a paper in The Journal of the American Medical Association.
Since sex kicks off such a complex set of biological responses, pinpointing an optimal orgasm count is probably impossible—not to mention unsexy. "I haven't seen any research that shows there's some critical number you need," Mintz says. Her prescription? "Whatever works."

Bed Time

How much sex are Americans having? It's hard to say, since surveys rely on participants' memory—and honesty. But Debby Herbenick, a sex researcher at Indiana University, thinks subjects love to spill: "You can't always be that candid about your sexual behavior."

• Most singles aren't swinging. Among 30-somethings, more than 77 percent of spouses have sex two-plus times a month. For singles, that's true of 36 percent of men and 17 percent of women.
• Youngins get busy. Forty-three percent of married men in their late 20s have sex twice a week or more, while 7 percent of husbands older than 70 do.
• The most active demo: married couples age 18-24. More than 60 percent get it on twice a week or more.