Most people learn the basics behind sex when Mom, Dad or the sex-ed teacher sit them down for a talk about where babies come from. And sure, sex is about reproduction. But it also has a number of pleasant side effects that aren't quite as well-known. Here are six things (safe) sex can do for you.
Sex may sometimes cause, ahem, performance anxiety, but fortunately there's a cure: Sex! OK, maybe it isn't as simple as that, but sexual activity has been shown to reduce anxiety in rodents and humans. A study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011597">published in July 2010</a> in the science journal PLoS ONE found that sexually active rats displayed fewer anxious behaviors compared with rats that hadn't been allowed to have sex (the study also found that sex protected the rats' brains from the negative effects of stress hormones).
Sex can relax people, too, according to a study of 24 men and 22 women who kept daily diaries of their sexual activity and then had to either do arithmetic or speak in front of a crowd. People who reported more sexual intercourse had lower blood pressure when performing these stressful tasks. (Unfortunately for onanists, the results didn't apply to <a href="http://www.livescience.com/animals/ten-masturbating-animals-sex-science-101019-1.html">masturbation</a>.)
Make you happy
No big surprise here: Sex and happiness go hand-in-hand. A 2004 study published in the economics journal The American Economic Review asked 900 American women how various daily activities made them feel and found that "intimate relations" topped the charts for happiness. (The morning commute was the most unpleasant daily ritual.)
A 2004 study of 16,000 Americans, published by the National Bureau of Economic Research, found that people who are happy tend to be the ones getting the most action. The study estimated that boosting between-the-sheets time from once a month to once a week was the <a href="http://www.livescience.com/culture/purchase-happiness-experience-100304.html">happiness equivalent</a> of getting a $50,000 raise. (Though type of sex matters: Men who paid for sex were less happy, as were people who cheated on a spouse.)
While you probably shouldn't get busy with someone with a cold, regular sex may boost your immune system. A study presented at the Eastern Psychological Association Convention in 1999 found that among undergraduate students, those who had sex once or twice a week had higher levels of the antibody immunoglobulin A, or IgA, compared with students who fooled around less. IgA is found in saliva and mucosal linings, and it is one of the body's first defenses against infections.
Don't get too excited, though: The study found that those who had sex three times a week or more had levels of IgA comparable to those who abstained from sex altogether, suggesting there's a happy medium. The researchers speculated that moderate sexual activity exposes you to other people's bugs, boosting the immune system, New Scientist magazine reported at the time. The sexaholics, on the other hand, may have been more anxious or stressed overall, which tends to lower immunity.
Soothe your pain
Orgasms don't just feel good; they ease pain. Research conducted at Rutgers University has found that women have increased pain tolerance and decreased pain detection during vaginal stimulation and orgasm. One 1985 study, published in the journal Pain, found that during vaginal stimulation, women saw increases in their pain threshold of about 36 percent to 40 percent. Around orgasm, women's pain threshold increased by 74.6 percent. The researchers are hoping they can isolate the chemical or brain response that causes this immunity to pain, enabling them to take the effect out of the bedroom and into day-to-day life.
Do you stress out about relationships? A regular sex life could ease your fears.
Newlyweds who score high in neuroticism – a trait marked by mood swings and frequent worry – <a href="http://www.livescience.com/health/sex-boosts-happiness-neurotic-newlyweds-101208.html">cope better in their marriages</a> when there's more sex. For most couples, frequency of sex at this stage of marriage wasn't associated with happiness, but neurotic spouses seemed to get a boost when things were active in the bedroom. Neuroticism tends to make people unhappy, but sex wiped worries away, making neurotic newlyweds as satisfied as their relaxed counterparts.
Reduce prostate cancer risk
Men, here's a good reason to get off: Ejaculation may reduce <a href="http://www.livescience.com/health/prostate-cancer-over-diagnosed-treated-100701.html">prostate cancer risk</a>. A 2004 study published in the Journal of the American Medical Association followed 30,000 men, including about 1,500 who eventually got prostate cancer, and found that an active sex life was not associated with a higher risk of the disease. Men who ejaculated the most – 21 times a month or more – were about one-third less likely to develop prostate cancer than those who ejaculated between four and seven times a month.
The jury is still out on when and if adding extra ejaculation to your life is helpful, however. Research on the topic has been somewhat contradictory and the protective effect of ejaculation is probably small. Perhaps the best approach is to have sex for sex's sake, and let the side benefits fall where they may.