En español | In the song "Sexual Healing," singer Marvin Gaye touts the emotional benefits of lovemaking. But did you know that, in most cases, sex is good for your physical health, too? Here's what the research shows:

See also: Brand new sex with the same old spouse.

1. Sex may boost your immune system. Regular moderate exercise boosts immune function, which helps prevent all manner of illness. At Wilkes University in Wilkes-Barre, Pa., researchers surveyed 112 subjects about their sexual frequency. They then analyzed their saliva for infection-fighting immunoglobulin A (IgA). Compared with the other groups, those who had sex once or twice a week showed significantly higher IgA levels. "Moderately frequent sex enhances immune function, and may help prevent illnesses such as the common cold," lead researcher Carl Charnetski says.

Studies show that an increase in sex can help men stay healthy longer. — Photo by: Tim Pannell/Corbis

2. It burns calories. Sex is moderate exercise. It burns about 150 calories an hour.

3. It lowers blood pressure. European researchers asked 51 healthy men and women ages 20 to 47 about their sexual frequency and then measured their blood pressure. As frequency increased, blood pressure decreased.

4.  It may lessen the risk of heart attacks. Many men worry that having sex might trigger a heart attack. Yes, it might, according to a recent Tufts study, but the risk is tiny and affects only those who rarely exercise. For those who are physically active, sex reduces the risk of a heart attack. Following 914 Welsh men for up to 20 years, British researchers found that as sexual frequency increased, heart attack risk decreased: "Middle-aged men should be heartened to know that frequent sexual intercourse offers some protection from heart attack."

5. It might ward off prostate cancer. For eight years, National Cancer Institute researchers tracked orgasms and risk of prostate cancer in 29,342 men, ages 46 to 81. As orgasms frequency increased, especially during the men's twenties, prostate cancer risk later in life decreased. Compared with men who reported seven ejaculations a month during their twenties, those who reported 21 or more were 33 percent less likely to develop prostate cancer decades later.

6.  It helps you relax.  Good sex is based on whole-body massage, which is deeply relaxing and reduces stress. Deep relaxation also helps treat an enormous number of ailments, among them: pain, asthma, high blood pressure, heart disease, depression and arthritis. "Regular sex with a loving partner offers similar benefits," says sex therapist Marty Klein of Palo Alto, Calif.

Next: Make love more often and prolong your life.