• Heart disease - lovemaking is a good aerobic exercise that improves the circulation and works the heart. Sexually active people tend to suffer less heart attacks possibly owing to their better fitness

• Weight - Intercourse can burn around 200 calories, not bad for a few minute workout and way more entertaining than a 30 minute churn on the treadmill

• Pain - endorphins released during orgasm can dull the chronic pain of backaches and arthritis as well as migraines

• Depression - Sexually active people appear to be less vulnerable to depression and suicide, perhaps because they are more comfortable with their sexuality

• Anxiety - Hormones released during arousal can calm anxiety, ease fear and break down inhibitions

• Immunity - Frequent intercourse may boost levels of key immune cells that help fight off colds and other infections

• Cancer - early studies hint that oxytocin and the hormone DHEA, both released during orgasm, may prevent breast-cancer cells from developing into tumors

• Longevity - Frequent orgasm has been linked to longer life; this may have something to do with sex's beneficial effects on the heart and immune system.

Now, before anyone gets carried away, a trial study of more than 100 college students in 1999 found that the levels of immunoglobulin, a microbe fighting antibody, in students who engaged intercourse once or twice a week were 30% higher than those who were abstinent. Curiously, those who had sex more than twice a week had the same levels as those who were celibate. Could there be an optimal rate of sexual frequency for keeping the body's defenses strong?