Having sex could lower your stress and your blood pressure.
That finding comes from a Scottish study of 24 women and 22 men who kept records of their sexual activity. The researchers put them in stressful situations -- such as speaking in public and doing math out loud -- and checked their blood pressure.
People who had had intercourse responded better to stress than those who engaged in other sexual behaviors or abstained.
Another study found that diastolic blood pressure (the bottom number of your blood pressure) tends to be lower in people who live together and have sex often.
2. Sex Boosts Immunity
Having sex once or twice a week has been linked with higher levels of an antibody called immunoglobulin A, or IgA, which can protect you from getting colds and other infections.
A Wilkes University study had 112 college students keep records of how often they had sex and also provide saliva samples for the study. Those who had sex once or twice a week had higher levels of IgA, an antibody that could help you avoid a cold or other infection, than other students.
3. Sex Burns Calories
Thirty minutes of sex burns 85 calories or more. It may not sound like much, but it adds up: 42 half-hour sessions will burn 3,570 calories, more than enough to lose a pound. Doubling up, you could drop that pound in 21 hour-long sessions.
"Sex is a great mode of exercise," Los Angeles sexologist Patti Britton, says. It takes both physical and psychological work, though, to do it well, she says.
4. Sex Improves Heart Health
A 20-year-long British study shows that men who had sex two or more times a week were half as likely to have a fatal heart attack than men who had sex less than once a month.
And although some older folks may worry that sex could cause a stroke, the study found no link between how often men had sex and how likely they were to have a stroke.
5. Better Self-Esteem
University of Texas researchers found that boosting self-esteem was one of 237 reasons people have sex.
That finding makes sense to sex, marriage, and family therapist Gina Ogden. She also says that those who already have self-esteem say they sometimes have sex to feel even better.
"One of the reasons people say they have sex is to feel good about themselves," she says. "Great sex begins with self-esteem. If the sex is loving, connected, and what you want, it raises it."
Of course, you don't have to have lots of sex to feel good about yourself. Your self-esteem is all about you -- not someone else. But if you're already feeling good about yourself, a great sex life may help you feel even better.