Next time you have a headache, just say yes. Stimulation of your clitoris and viginal walls triggers the release of endorphins, corticosteroids, and other natural painkillers. As a result, you’ll feel less pain from headaches and sore muscles during sex. The benefit, which begins before you orgasm, can linger for up for 2 days, says Barry Komisaruk, PhD, a Rutgers University psychology professor and coauthour of The Science of Orgasm. In his research, he found that women could withstand painful pressure to their fingers while they were stimulated by sex toys; during orgasm, apin tolerance doubled. And self-stimulation through the front wall of the vagina, where some find their G-spot, increases pain tolerance and pain detection thresholds by up to 50%, reports Komisaruk.

During arousal and orgasm, your levels of “happiness” hormones rise. Two of these – oxytocin and DHEA – may help keep breast cancer free. One study showed that women who have sex more than once a month have lower risk of developing breast cancer than those who are lesss sexually active. And Greek reseacrhers found that men who had at least seven orgasms a month in their 50s had a significatly lower chance of developing male breast cancer.

Cardiologists rank intercourse as a mild-to-moderate-intensity exercise that enhances heart health as well as brisk walking does. As with any workout, the more vigorous you are, the more your heart benefits. The positions you try matter too; being on top is especially cardiac-firendly because it usually requires more effort. Orgasm delivers a bonus: At your peak moment, your heart rate may hit 110 beats per minute, comparable to what you might achieve when walking quickly or jogging.

Catholic priests have an elevated chance of dying of prostate cancer, and studies point to celibacy as a factor. In 2003, research on middle-aged Australian men found that those who averaged at least four ejaculations a week had a one-third lower chance of developing prostate cancer than those who had fewer. “When you drain the pipes, as it were, you have less clogging,” says Irwin Goldstein, MD, heas of sexual medicine at Alvarado Hospital. Though the results of the study were clear, the reasons they occurred were not, says Goldstein, who calls for more research.

Got a BIG presentation coming up at work? A 2005 study found that men and women who had engaged in intercourse in the 2 weeks before a stressful day had an easier time while doing public speaking and some verbal arithmetic. During their presentations, their systolic blood pressure (the first number in a blood-pressure reading) increased less and then dropped back to its normal level at a faster rate than that of people who had no sexual relations or had other form of sex, including noncoital interactions or masturbation. One theory about why this occurs is that intercourse requires more complex brain activity; another idea is that it stinulates a number of important nerves not triggered during other sexual activity.

Research from Wilkes University showed that college students who egaged in sex once or twice a week has 30% higher levels of infection-fighting antibodies than did their abstinent antibodies than did their adstinent classmates. In 2004, German scientists produced similar results: Blood tests showed that arousal and orgasm in men increased levels of certain pathogen-fighting white blood cells. The effect is comparable to that of other stress-busting activities, such as exercise and listening to music, which also boost secretion of certain proteins that defend the body against infection.

Scientists in New Jersey found that postmenopausal women who had sex realtions more than 10 times a year had less evidence of viginal atrophy than those who reported less frequent sex. That’s sign of healthy tissues, says Sandra Leiblum, PhD, a New Jersey sex therapist who helped conduct the study. Arousal brings blood to the vagina, which delivers nutrients and oxygen. Keep using this part of your body, and you’ll help prevent the tissue from becoming thinner nd less elastic as you age, so inetrcourse can remain comfortable and pleasurable.