Life Science

Why do guys get sleepy after sex?

-- asks J. from Brooklyn, NY.

September 25, 2006
The sated Satyr. [<em>Sleeping Satyr</em>, marble copy of bronze original, unknown sculptor c. 200 B.C.]
The sated Satyr. [Sleeping Satyr, marble copy of bronze original, unknown sculptor c. 200 B.C.]

For many women, the correlation between sex and snoring is one of those annoying facts of life: no matter when passionate encounters occur, men always seem to fall asleep immediately afterwards. Dave Zinczenko, the author of Men, Love and Sex: The Complete User Guide For Women, explained the phenomenon to Huffington Post writer Arianna Huffington this way: “Men go to sleep because women don’t turn into a pizza.”

I doubt I am ever going to become a pizza, and I’ll never have the foresight to order one beforehand. So in lieu of a cure, a better explanation will have to do. Although women sometimes feel sleepy after sex, the phenomenon does seem more pronounced in men. What is it, then, that spirals them into the land of nod?

First, the obvious reasons for sex’s somnolent sway: the act frequently takes place at night, in a bed, and is, after all, physically exhausting (often more so for the man than the woman, although this certainly varies). So when sex is over, it’s natural for a guy to feel sleepy.

Secondly, research using positron emission tomography (PET) scans has shown that in order for a person to reach orgasm, a primary requirement is to let go of “all fear and anxiety.” Doing so also tends to be relaxing and might explain the tendency to snooze.

Then there is the biochemistry of the orgasm itself. Research shows that during ejaculation, men release a cocktail of brain chemicals, including norepinephrine, serotonin, oxytocin, vasopressin, nitric oxide (NO), and the hormone prolactin. The release of prolactin is linked to the feeling of sexual satisfaction, and it also mediates the “recovery time” that men are well aware of—the time a guy must wait before “giving it another go.” Studies have also shown that men deficient in prolactin have faster recovery times.

Prolactin levels are naturally higher during sleep, and animals injected with the chemical become tired immediately. This suggests a strong link between prolactin and sleep, so it’s likely that the hormone’s release during orgasm causes men to feel sleepy.

(Side note: prolactin also explains why men are sleepier after intercourse than after masturbation. For unknown reasons, intercourse orgasms release four times more prolactin than masturbatory orgasms, according to a recent study.)

Oxytocin and vasopressin, two other chemicals released during orgasm, are also associated with sleep. Their release frequently accompanies that of melatonin, the primary hormone that regulates our body clocks. Oxytocin is also thought to reduce stress levels, which again could lead to relaxation and sleepiness.

What about the evolutionary reasons for post-sex sleepiness? This is trickier to explain. Evolutionarily speaking, a man’s primary goal is to produce as many offspring as possible, and sleeping doesn’t exactly help in his quest. But perhaps since he cannot immediately run off with another woman anyway—damn that recovery time!—re-energizing himself via sleep may be the best use of his time.

And although there is conflicting information as to whether women feel sleepy after sex, a woman often falls asleep with the man anyway (or uses it for some key cuddling time), which is good news for him: it means she is not off finding another mate. When the man wakes up and she’s still there, he just might be ready to go again.

It’s also possible that sleepiness is just a “side effect” associated with a more evolutionarily important reason for the release of oxytocin and vasopressin. In addition to being associated with sleep, both chemicals are also intimately involved in what is called “pair bonding,” the social attachment human mates commonly share. The release of these brain chemicals during orgasm heightens feelings of bonding and trust between sexual partners, which may partially explain the link between sex and emotional attachment. This bond is favorable should the couple have a baby, as cooperative child rearing maximizes the young one’s chances for survival.

The bottom line is this: there are many potential biochemical and evolutionary reasons for post-sex sleepiness, some direct and some indirect—but no one has yet pinpointed the exact causes. One thing, however, is certain: we females better get used to it, because it doesn’t look likely to change anytime soon.

I will leave frustrated American women with one final thought: if you are upset at the ubiquity of the post-sex snoring phenomenon, remember that things could be a lot worse. A recent survey of 10,000 English men revealed that 48 percent actually fall asleep during sex.

Talk about coitus interruptus!

About the Author

Melinda Wenner

Melinda Wenner gave up a much higher salary, a BMW and a comfortable life in the British suburbs in order to write for Scienceline. She is willing to trade her knowledge of molecular biology (and perhaps her list of sources) for a well-poured pint of Carling. Contact her at



We are lean of course until you overdose on the SAD diet (Sad American Diet).

Frank Gotch and George Hackenschmidt were sports superstars of their era.
The respiratory rate should drop below the heart rate after 10 minutes.

Michael says:

It’s great to be gay! We both fall asleep!

Annie Steward says:

So this is where it has come to – We are just self centered animals , after all ?

Wow – so many lies . First of all , we are created in the image of our Creator . We have

spirits and we have souls . We are created for soul connection with someone else , and

science proves it . When these chemical are released , a strong bonding takes place .

This is what God intended us to to feel with a husband or wife – a relationship based

on LOVE and strong bonding . It’s a strong beautiful relationship .

Seth says:

That’s just an opportunity to really shine boys!! Commit and follow through!! That’s why God gave you hands and tongues. Just because the roller coaster is down doesn’t mean the park is closed. Good piece Melinda…

Bayer Scott says:

American is changing for the best i can say this because the gay community just literally got liberated i mean we can officially get married and be part of the the American society. When i heard the news i was filled with joy i mean me and my fiance the man i have always can finally own our marriage certificate in Georgia.It was not always right for us if you know what i mean. Before we got married in California ,he was not in love with me or i would say he was in love with me and lost for another guy and it was frustrating.We were off and on and mostly times our break up was always bad it always ends with huge fight. I loved him and wanted to be all his for the rest of my life but he did not see that he wanted to have me to himself and still see other guy i mean who does that? He was the queen of heart breaker and also was perfect when he wants to mend the heart. This was why i also went back to him no matter what always led to our ugly break up. But this madness just kept going on over and over with us and like i said i was sick of it. You can’t hurt me over and over again and still come back to me i mean i am not a play thing you use and drop when you tired. Judge me if you will it not like i care because all my life people have always said trash about me but if i had paid their attentions i would not have been this happy. After searching for means to make him commit to me even taking him with me to couple counseling i decide i contact a spell caster called Obudun Magonata it was just an arbitrary choice i mean, i told myself if he can’t help me i will move on with my life maybe the one i clam to be the love of my life was not the one after all. Obudun Magonata is an angel sent from a place i don’t know.He save me and made me he happiest man on earth or more preferable the happiest gay man on earth . I don’t know how he did it just after he help me cast a love spell, every pain that i was going through was lifted of my shoulder like magic my lover became the queen of hearts i would say he became mine and loved me like his life depended on it.When i first contacted Obudun Magonata, he told me to come down to his temple so i may witness the greatness of his work we got the materials we used for the spell together and just after four day i say the greatness of his power.But i spent a lot Because i had to travel all the way to Africa.It will be cheaper for me to have had him get the materials form me but i was foolish. But its amazing i still got my heart desire. He also told me that the gay community will soon be free and in just two months his prophecy has come to pass. Who wants to tell me he is not great contact i you will here you will not regret your decision use thus address spiritsofobudunmagonata@ ( yahoo ). com rewrite to a normal email format- says:

This page certainly has all the info I wanted concerning this subject and didn’t
know who to ask.

furman english says:

I’m tired now and by myself.

Adrian says:

The most I’ve stayed hard in a row is after 5/6 orgasms. Recently, I hit 5 while masturbating… But they were in rapid succession. I knocked out for about ½ an hour. (All I remember is waking up in my chair then walking to my bed.)

weston Ab says:

Wander why it takes me an hour or two to ejaculate but my partner is having 6 or 7 a go round she seems happy but soar but why she doesn’t move

weston Ab says:

Wander why it takes me an hour or two to ejaculate but my partner is having 6 or 7 a go round she seems happy but soar but why she doesn’t move all to much and has trouble walking in a straight line afterwards

Msorgasmos says:

I get tired after I masturbate. I can masturbate and sleep all day. I think I have an issue. Cant cum during sex but don’t feel accomplished unless I get the other person off. Girls tend to wanna go longer and that can be exhausting. Guys fall asleep normally and that gives me time tp recover physically lol.. I am a female

Luna Lovegood says:

It also happens when you masturbate. You get sleepy. That is, if you are lying down when you masturbate. Sitting down while masturbating doesn’t have the same effect.

Nicrol says:

I am a student from a Chinese university and I had a conversation with my classmates after reading your 2006 article called “Why do guys get sleepy after sex?
Although I share your view that it is easier to get sleepy after masturbation to orgasm and more conducive to sleep. But my classmate, he didn’t think so.
His point of view is as follows.

① Masturbation or sex will secrete adrenaline and cause a rapid heartbeat, because a rapid heartbeat can affect people’s ability to fall asleep, and there is a saying that the effect of adrenaline lasts for about an hour (see attachment for details), so he thinks that masturbation or sex will keep the heartbeat accelerating afterwards, so it is not good for sleep.
② He does not deny your opinion that hormones including oxytocin and melatonin are related to sleepiness or beneficial to sleep. But he doubts whether the doses of these hormones you suggest, especially during masturbatory orgasm, can counteract the effects of adrenaline and successfully make people more sleepy. If not, then the masturbatory orgasm is more conducive to sleep not because of these hormones.

In summary, his belief that masturbation or sex is more sleepy is unscientific or wrong and factually incorrect. Although I agree with your statement that I feel sleepy from the perspective of actual physical examination, my classmate’s statement still concerns me a lot. I hope you can answer how adrenaline and the hormones that you said are beneficial to sleep work in physical strength, and whether they interact with each other? Is the dose of those sleep-friendly hormones secreted enough to make people more sleepy? If so, what would be the result? Thank you very much.

If possible, can you respond to this query to solve my inner confusion? Thank you very much!

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