8 Things You Didn't Know About Orgasms

Sex researchers Masters and Johnson labeled "intense orgasms" (like the kind where Sally's not faking it) as involving 8 to 12 vaginal contractions, each lasting 4.0 to 9.6 seconds. That adds up to over two minutes of continuous mind-bending bliss.

Not even scientists can agree on what percentage of women regularly climax, or how or even why. But it's generally accepted that roughly a third of women are unable to have orgasm through any means, says Cindy M. Meston, PhD, who was the chair of the World Health Organization's 2005 orgasm committee (yes, there was such a thing). Recent research has confirmed that anatomy plays a role: Some women are just born to orgasm -- and some have to work at it. A study published last year in the journal Hormones and Behavior confirmed that the shorter the distance between a woman's clitoris and vagina (less than 2.5 centimeters is ideal), the easier it is for her partner to stimulate her supersensitive areas (tools and toys can help bridge the gap). Regardless of how we're built, almost every woman is aware of the other big challenge: Orgasms tend to require more constant attention -- about 20 minutes, studies show -- than most busy people have the time or concentration for.

Working out at the gym? Sleeping on an airplane? Giving birth? Women (perhaps even you!) have reported experiencing orgasms in all of these unconventional situations. This has nothing to do with subconscious fantasies: Spontaneous, non-sexual orgasms can be caused by increased blood flow to the genitals combined with vibration or contact with the clitoris (during labor, there are also massive surges of ecstasy-inducing hormones like prolactin, oxytocin and beta-endorphins). Exercise-induced orgasms, in particular, seem to have been the gym addict's best-kept secret, until a study late last year by human sexuality researchers at Indiana University revealed that about a quarter of the 530 women they interviewed had climaxed while working on their abdominals, riding a bike or lifting weights.

Research has shown that orgasms experienced during sex cause us to release 400 times more prolactin -- which tends to make people feel sleepy and satiated -- than from those from masturbation, writes Meston in Why Women Have Sex, a book she co-authored with psychologist David M. Buss. This is why women may still feel alert enough to write a status report or clean the bathroom mirrors after a self-induced pleasure session. It all makes evolutionary sense, say the authors, because post-sex sleepiness helps women lie still, which is the optimal position for conception.

The surge of oxytocin that occurs during orgasm triggers a release of feel-good endorphins that act as powerful pain relievers. Even better, Meston says, while medication can take more than a few minutes to kick in and then lose power after a few hours, orgasms relieve pain immediately and last for the rest of the day or night. She suggests this could be because orgasms offer a custom-made treatment prepared by your own body chemistry. Don't have a problem with headaches? The orgasm cure can also work on arthritis, backaches and muscle pain.

You're familiar with your cervix -- the opening to the uterus at the far end of the vagina -- but you probably haven't thought of it as a sexual organ. Some women love the feeling of rhythmic pressure on their cervix (Meston has heard it described as an exciting intersection of pain and pleasure) and may depend upon that sensation to reach orgasm. But even if a woman has the flexibility of a champion pole dancer, she can't do much to shorten the distance to her cervix -- and that's when a longer, um, instrument can come in handy.

When the uterus contracts during orgasm, it can help use up cramp-causing prostaglandins, flush out excess blood and even clear out some of the lining and debris that could flow backward and lead to endometriosis, Meston says. If having sex during your period makes you feel squeamish or just physically uncomfortable, Meston suggests going straight for the fix by taking matters into your own hands.

Research shows that women have more -- not to mention more fulfilling -- orgasms as they get older, says Debby Herbenick, a research scientist at Indiana University. In an analysis of 3,990 adults ages 18 to 59, she and other sex researchers found that an impressive 70 percent of women in their 40s and 50s were sent into orbit the last time they had sex -- which was higher than the number of happy postcoital customers in their early 20s. While the study didn't delve into causes, it's likely that older women are more comfortable with their bodies, their partners and their own desires. They've also had enough erotic experience to know what revs their engines as well as what causes them to really take off.