It actually lengthens it......if a man has 100 orgasms a year he can add ten yrs to his life. If a women has 50 I beleive she adds 7 years to hers. I believe this is was published in one of Dr Roizen's books out of the Cleveland Clinic (Real Age Makeover I think) and it is based upon the release of oxytocin and its effect on melatonin/prolactin and its effects on PPAR gamma and energy metabolism. So I think having sex makes you live longer not shorter.

I think you are going to find actual sex has less of an effect than the levels of sex hormones because human culture is so weird. There is ample evidence that men with very high testosterone levels die earlier, though there are some confounding factors there since that hormone is linked to aggressiveness and recklessness. However, often high-testosterone men, unlike high-testosterone gorillas, don't have much sex because they are a marginalized population in modern society, since they are not very good at keeping jobs and many are imprisoned. Prison inmates have high testosterone levels. Even women can struggle with high testosterone, but there is evidence that high levels of any sex hormone like estrogen can be bad for you.

Also, the people having the most sex in our society are not often the ones reproducing at the highest rate. I'm quite certain that having babbies can be exhausting to the female body. I'm not sure about semen and men, there is some evidence that masturbation semen prevents prostate cancer. It's true that Taoists say that it exhausts the body and mind, but most religions say that. It DOES supposedly increase testosterone though, which might be good for some men and bad for others.

Interestingly, though we associate cavemen with masculinity, hunter-gatherer men generally have lower levels of testosterone than American men.

You probably know that certain schools of Taoist sexuality hold that retention of semen is important to male longevity and health. Now some of these schools opt for celibacy and other for practicing a form of coitus reservatus. Of course, as far as I know, we have no scientific findings to support such a notion.

[TMI WARNING]

I practice coitus reservatus just to prolong sexual, however, I also notice that at my age when I do ejaculate, it sort of depletes me of energy.

By the way Kamal, you look a lot like Audrey Tautou!

Humans are made to have sex all the time, no matter season or partner's ovulation. It's a pretty good exercise, HIIT in a way ;-). All the hormones that are released are beneficial to our health, looks and satisfaction. It helps in relaxation, creates intimacy (and we know that social relations are crucial for human survival),

I think for us today sex is a source of stress more than all the positive things. We have to fit it into schedule, we are stressed that we wouldn't get enough sleep, we have too much worries on our mind, too much self-esteem issues and ridiculous expectations. Cortisol should have no room in intimate relations, but modern life is cruel.

I remember reading about more traditional sleep styles, where people were sleeping often in 4-5h blocks with 1-2h break, when people either just lied in semi-sleepy, drifty, relaxing stage, or often engaged in sex, with no pressure, no stress.

what a glorious shortened lifespan...!

I don't know about frequency of sex as it relates to lifespan, but evolutionary biologist Michael Rose found that he could extend the lifespan of fruit flies by postponing the age at which they reproduce.

When I first read about this, I instantly thought of the strange (strange to me, someone who matured quite early) Western push to extend childhood well into late adolescence, especially prohibitions on sexual behavior/marriage. At sixteen, both I and my girlfriends were quite biologically ready for sex, and I'm certain that almost any earlier or non-Western culture would have considered us perfectly marriageable, just based on physical maturity; perhaps even a little past the prime age.

It's a stretch, but I wonder if somehow we've instinctively grasped that postponing reproduction is better for longevity. I have no idea at all how we would intuitively grasp that, but, well...it's a thought, anyway. ;/

My answer is "WHO CARES!? YOU ARE HAVING SEX!" I mean, really. I'm not a Grok re-enactor or anything, but frequency of copulation, along with frequency of quality feed, resulting in increased number of offspring - would have been a very Paleo "sign of success".

Maybe another factor to be considered is how you define 'sex'. Is this being purely limited to the act of intercourse itself or the wider definition?

Having sex can be as wide-ranging as simply kissing, cuddling, or massaging your partner, a candle-lit room, pleasant scents, or performing other intimate acts. Those acts all have a positive influence on the body by de-stressing, reducing tension, relaxing muscles and so on. Those factors are often likely to be as beneficial in the long term.

I'm not suggesting that you need to be in a long-term, monogamous relationship for this but a bit of tenderness goes a long way sometimes rather than just focussing on the reproductive act.

You mentioned worms living longer when they ate less and did not reproduce as much. I would say the extended lifespan was not due to decreased reproduction but the decreased caloric intake. Decreased sex seems like an effect - if calorically restricted worms and humans would default to repair mode and quit wasting energy on gametes.

I'm open to a looking over a study done specifically on limiting reproduction in humans and its effects, but from a simple biological point of view, reining onesself in doesn't make much sense.

I would think that if there was a natural meaning to life; it would be to pass on your most desirable traits to the next generation. So wouldn't that mean your body would be geared to procreate as much as possible for as long as possible to ensure that your best traits are paired with the best traits of a multitude of partners.

I don't see how frequency of sex could possibly make any different to a woman. We're only fertile for 24 hours per month, and the changes our bodies go through before and after ovulation happens regardless of whether we're having sex at all.

Men, on the other hand... if ejaculation and sperm production is a strain on the body, they are in trouble. Maybe that's why they live 5 years less than women on average. ;)

We have examples in monks. Did Catholic monks who practiced celibacy live longer? How about Buddhist monks?

There has to be some study on the longevity of those who practiced celibacy. In Buddhist monks, we would have both celibate and vegetarian lifestyles.

Unfortunately, such people also lived "clean" and they probably lived longer than their non-celibate counterparts.

Yes. I guess so.

I think the primary reason why having sex shortens lifespan is because sex is strenuous. As a man, I feel very, very tired after having an orgasm. I also become irritable and less stable after.

There is also this flood of 'hormones' that we get when we seek new partners. They also add more stress to our body. Also leaving our sex partner creates another stress point.

I believe that the best factor for longevity is homeostasis (balance). All this hormones creates imbalance that affect our health.

Someone said something about (happily) married couples living longer. I have research that too and its found that these kind of couples actually engage sex in lesser frequency than promiscuous people. Instead they engage more in bonding behaviors (cuddling, touching, kissing, etc.). While sex give us the high and intense pleasure, bonding behaviors are relaxing and gives us sense of safety and satisfaction. Bonding behaviors (from our loved ones) is also related to many health benefits like faster healing, stronger immunity to disease, resistance to stress, and others.

But then it is found that separated/divorced/unhappy couples are 3x likely to die.

Maybe a means to live longer is to have a loving partner and engage with lots of bonding behavior with him/her and avoid disharmony.

Pretty sure you're doing it wrong if it shortens your lifespan :)

Frequent ejaculation offers some protection against prostate cancer:

Leitzmann MF, Platz EA, Stampfer MJ, Willett WC, Giovannucci E (April 2004). "Ejaculation frequency and subsequent risk of prostate cancer". JAMA 291 (13): 1578–86.

Giles GG, Severi G, English DR, McCredie MR, Borland R, Boyle P, Hopper JL (August 2003). "Sexual factors and prostate cancer". BJU Int. 92 (3): 211–6.

STDs? or is it STIs now...?

If having lots of sex shortens lifespan.....may I die young and with a smile on my face!

I do believe that having lot of sex do shorten once lifespan since the level of energy lost is to high compared to energy gain. The body needs energy to produce now red blood cells(Average lifespan of 120 days ) to replace worn-out red blood cells ,so with this energy used on sex practiced the level of red blood cells will reduced and hence shortage in blood leading to quick dead.