1. A longer life
In a British study, men who had intercourse at least twice a week lived longer than men who had sex less than once a month. A U.S. study had similar findings, and a Swedish study examining the sex lives of 70-year-olds found that men who died before their 75th birthday had ceased having sexual intercourse at earlier ages.
The Swedish study didn't find that women lived longer if they had sex more frequently, and neither did a study in North Carolina. However, in the North Carolina study, women who reported enjoying sex more lived longer than those who didn't report enjoyment.
2. A healthier heart
In a British study, people who had intercourse twice a week or more were less likely to have heart attacks and other fatal coronary events. Those who had sex less than once a month had twice the rates of fatal coronary events, compared with those with the highest frequency of intercourse.
3. Lower blood pressure
In a study published in the journal Biological Psychology, people who had sex more often tended to have lower diastolic blood pressure, or the bottom number in a blood pressure reading. Brody's experiment, in which more sexually active study subjects had markedly less dramatic blood pressure spikes when they were put under stress, also supports the benefit.
4. Lower risk of breast cancer
A French study found that women who have vaginal intercourse not at all or infrequently had three times the risk of breast cancer, compared with women who had intercourse more often.
5. Lower risk of prostate cancer
A Minnesota study found that men who'd had intercourse more than 3,000 times in their lives had half the prostate cancer risk of those who had not. While it's not clear why this would be true, studies have found that men who had more intercourse tended to have better prostate function and eliminated more waste products in their semen. "These differences could conceivably impact prostate cancer risk," Brody writes in his article.
6. Pain relief
Whipple and others have conducted studies suggesting that more sexual activity helps relieve lower back pain and migraines.
7. A slimmer physique
A study of healthy German adults revealed that men and women who had sex more frequently tended to be slimmer than folks who didn't have as much sex. Sex burns 50 to 60 calories per encounter, Whipple says, so sex three times a week for a month would burn about 700 calories -- or the equivalent of jogging about seven miles.
8. Better testosterone levels
A group of men being treated for erectile problems saw greater increases in testosterone when, along with the treatments, they had frequent sex. Specifically, men who had sex at least eight times per month had greater increases than those who had sex less than eight times per month.
9. Fewer menopause symptoms
Menopausal women in Nigeria experienced fewer hot flashes when they had sex more frequently. Brody says this may be because sexual activity helps regulate hormonal levels, which in turn affect the symptoms of menopause.
10. Healthier semen
In three studies, men who had frequent intercourse had a higher volume of semen, a higher sperm count and a higher percentage of healthier sperm, compared with men who tended to participate in other sexual activities.