Six Reasons to Have Sex Every Week

Sex is good for adults. Indulging on a regular basis—at least once a week—is even better. Research links sex (with all safer-sex precautions taken) to an astonishing array of physiological benefits, from longevity to pain relief. Many studies don't address whether the health bonus comes from the act itself or from the corresponding emotional intimacy, but the bottom line is that getting physical has some great side effects—especially for women. Here are six ways that sex boosts your health:

1. It Fights Colds and Flu. Sexual intercourse once or twice a week raises the body's level of the immune-boosting antibody immunoglobin A by a third, according to research at Wilkes University in Pennsylvania.

2. It's a Beauty Treatment. In a study at the Royal Edinburgh Hospital in Scotland, a panel of judges viewed participants through a one-way mirror and guessed their ages. Those who looked seven to 12 years younger than their age (labeled "superyoung") were also enjoying lots of sex—four times a week, on average. OK, maybe they were having so much fun because they looked young. But it's likely the sex was helping, researchers say. One reason is that it raises a woman's estrogen level, which helps make hair shiny and skin supple.

3. It Burns Calories. A little over four calories a minute, or the equivalent of four Hershey's kisses in a half hour of love. Think of it as part of your weekly exercise regime, and burn, baby, burn.

4. Yes, Honey, I Have a Headache. For a woman a migraine might actually be a reason for making love rather than avoiding intercourse: the increase in endorphins and corticosteroids during arousal and orgasm is analgesic.

5. It Promotes Regular Menstrual Cycles. A series of studies by behavioral endocrinologist Winnifred Cutler and colleagues at Columbia and Stanford universities found that women who have intercourse at least weekly (except during their period) cycle more regularly than abstainers or the sporadically active. (Related research found that lesbian lovemaking also smoothes out menstrual cycles.) Cutler argues that intimacy is essential, not orgasms: "Regular exposure to a loving partner has extraordinary effects on health and well-being."