If you are already eating your fruits and vegetables, exercising and taking your vitamins, you might ask what more you can do for your health. One answer might please you: Have more sex.

While the impact of sexual activity on health is not a major topic of research, common sense and a handful of studies suggest that sex can be good for your health. So consider these potential fringe benefits the next time the opportunity for (safe) sex arises:

Erotic Exercise
Even though sex probably involves less energy expenditure than most aerobic exercise, it can give you a workout, depending upon how vigorous it is. After all, sex, and particularly orgasm, involves the contraction of muscles in the arms, legs and abdomen. Also, your heart and breathing rates rise when you are sexually aroused just as they do when you exert yourself on the playing field or at the gym. Another bonus is that you're likely to drift off into a deep, luxurious sleep after you tire yourself out.

Since sex requires some stamina, it appears that people who are physically fit may be more likely to have satisfying sex than people who simply shift from their office chair to their couch. Regular exercise may make sex better because it improves muscle tone, cardiovascular fitness and mental health.

A Happy Heart
British researchers who looked at about 900 middle-aged men found that men who had sex twice or more a week had a lower risk of heart attack over the course of 10 years than men who had sex less often. The study was published in 2002 in the Journal of Epidemiology and Community Health. The cardiovascular boost may be from the sex itself, or may be because men who are in better physical condition have regular sex, so their heart attack risk is already lower.

For Her
One study suggests that sexual activity might prevent endometriosis, a common gynecological condition that occurs when the tissue lining the inside of a a woman's uterus grows in other places, such as on the ovaries or fallopian tubes. This growth can cause pelvic pain and sometimes infertility. The study, published in 2002 in the journal Gynecologic and Obstetric Investigation, found that women who were sexually active during menstruation were 1.5 times less likely to develop endometriosis than women who didn't have sex during their periods. The researchers also found that orgasm during menstruation lowered risk.

According to study author Harvey J. Kliman, MD, PhD, a research scientist at Yale University School of Medicine in New Haven, anything that contributes to menstrual debris going backwards into pelvis might increase risk for endometriosis. The contractions of the uterus that occur during sex, and specifically orgasm, may help push the menstrual debris out of the uterus, Dr. Kliman explains.

For Him
While sexual activity has been thought to increase risk of prostate cancer, newer research, including a study published April 7 in the Journal of the American Medical Association (JAMA), indicates that frequent ejaculation might help protect the prostate from cancer. This study supports a smaller Australian study from 2003 that found that that men in their 20s who ejaculated more then five times a week were one-third less likely to develop aggressive prostate cancer than men who ejaculated four to seven times a month. Ejaculating regularly might lower risk because cancer-causing substances get flushed out of the body in the seminal fluid, instead of staying in the prostate.

Stress Relief
Satisfying sexual activity can, of course, be an exhilarating mood lifter. If you're in a relationship, says Carol Rinkleib Ellison, PhD, a San Francisco&endash;based psychologist and author of Women's Sexualities, sex can "bring the relationship into harmony and make you and your partner feel closer, so you feel less stressed and more relaxed." And whether you are having sex with a partner or masturbating, orgasm itself can also help release tension. The surge of a hormone called oxytocin that occurs during orgasm may account for the both the stronger emotional connection and the tension relief. Oxytocin appears to regulate blood pressure and temperature and even relieve pain and promote the healing of wounds. Dr. Ellison compares orgasm to "re-booting" your body and mind just as you would re-start a computer. But she notes that focusing on orgasm too much can be stressful and sometimes self-defeating. Instead, people should think about successful sex as "mutual erotic pleasure in whatever form it takes."