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Why Do Men Feel Sleepy After Sex? Prolactin, Oxytocin, Vasopressin, et al.

After sex it is very common for men to feel tired or even fall asleep on their partners. There are a set of specific reasons as to why this tiredness occurs. In most cases it is a combination of exerting a lot of physical energy during sex as well as the chemicals that are released when the act is complete and orgasm is achieved. In the article that I wrote regarding anxiety – I listed that one of the best cures is sex – and that’s because it takes away stress and in order to achieve orgasm, it is said that a person needs to let go of all fear. Although not every man will feel tired after sex, most do report feeling more relaxed.

Why do men feel sleepy after sex and ejaculation?

1. Prolactin

When a man orgasms, prolactin is released – a hormone that is linked to feelings of sexual satisfaction. The primary reason a man feels tired after sex is due to the fact that prolactin causes sleepiness and drowsiness. During sleep people have higher levels of prolactin. In studies involving prolactin injections into animals, they became tired immediately.

The reason a man cannot simply go for another round immediately after having sex has to do with the fact that their prolactin levels are very high. When the prolactin levels dip again, the man will be ready for another round. There is a relationship between prolactin and dopamine – increased dopamine can act as a prolactin inhibitor. Some research has demonstrated a link between prolactin-deficiency and fast recovery times after sex.

It should also be noted that prolactin levels after orgasm during sex are 4X higher than those after masturbation. So masturbation in general is not going to make you feel nearly as tired as a full blown sex session.

2. Oxytocin

This is sometimes referred to as the “love hormone” because it promotes bonding between partners. In general it promotes love and trust of people that are intimate with each other and can also cause increased social relaxation. The fact that people feel more relaxed around each other eliminates most fear and anxiety (both stimulants). Because the body is nearly void of natural stimulants and stress after sex, people are naturally going to feel tired and in lounge mode.

3. Vasopressin

Vasopressin has been linked to cerebral tiredness. It is a hormone that primarily helps constrict blood vessels and control water retention. It plays a vital role in helping our body regulate homeostasis and plays a role in sex and social behavior. It increases our ability to bond and can reduce stress. Although it is a fairly complex hormone, the fact that it may be released directly into the brain after sex is thought to help increase the relaxation along with oxytocin.

Source: http://www.ncbi.nlm.nih.gov/pubmed/4145418

4. Neurotransmitters

During ejaculation, men release norepinephrine, serotonin, and NO (Nitric Oxide). It is the combination of different chemicals and neurotransmitters that are released into the system that leads to relaxation. There are more than these three released of course, but these are some of the more common neurotransmitters that are released. Serotonin is known to have a calming effect on the brain as well as the body. Nitric oxide is released by the prostate gland and basically promotes relaxation throughout the entire penis.

5. Parasympathetic Relaxation

After sex, the parasympathetic nervous system takes over and the sympathetic is put to rest. Parasympathetic responses promote physical relaxation, blood flow to the extremities, and calmness. In order to reach orgasm, it has been reported that a man must have no fear or let go of all stress. The combination of relaxing chemicals and neurotransmitters override the production of epinephrine and reduce dopamine (a stimulating neurotransmitter) after orgasm. Plus the act of being intimate with another person really helps to further reduce anxiety. If your fight or flight response is literally shut down during orgasm, it is no wonder that you feel a little more tired than usual.

6. Physical Exertion

Usually the man is the one doing more work physically while having sex in comparison to the woman. Women typically don’t have to do much other than lay back or go for a ride so to speak. It is the man that does the thrusting and if the sex session lasts awhile, he may end up getting pretty tired by the time things come to an end. Some partners have sex for over an hour and when a man is doing a lot of physical work to please his partner, he gets tired.

7. Sex at Night

Most people have sex towards the end of the day or at night and after a long day already, it is pretty natural to feel tired. One last “bang” before the night ends is what does it for most men – especially if the sex is very late at night. It is natural to feel tired at night, and after orgasm, it’s a double whammy of tiredness from the hormones, chemicals, and neurotransmitters that flood the body and brain. Your best bet at this point is to just chalk it up and get a good night’s sleep. Sex can be one heck of a good remedy for insomnia if done at an appropriate time at night.

How to combat the post sex sleepiness?

If you feel tired after sex, probably the best thing you could do for yourself is give into sleeping. If it is at night, you probably don’t care and are going to sleep anyways, but if it’s in the afternoon, you may want to consider taking a nap. If you don’t want to take a nap, you could always make sure that you have some sort of stimulant around like caffeine. Go grab a cup of coffee or make yourself go do something.

Really the only other way to combat post sex tiredness is to lower your levels of prolactin. Probably the best way to counteract high prolactin levels is with some sort of stimulant that increases dopamine. Dopamine levels keep increasing until orgasm, and then the prolactin takes over. It’s best though to simply rest for awhile before having another sex session – who doesn’t like the satisfaction from the prolactin being released – it feels great.

Note: Many scientists believe it is a natural evolutionary response to feel sleepy after sex for men. It is hypothesized that the prolactin helps prevent a man from running off with another partner, or hopping to another woman’s bed.

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{ 12 comments… add one }

  • Ryan Oliver Dakura January 19, 2014, 9:02 pm

    I dont feel sleepy at all i can work right away,if i have a active partner i can have another one nd i prefer working hard as if nothing ever happened,what is wrong wth me.

    • GLOOM February 27, 2014, 2:43 am

      Nothing is wrong with you. Not everyone feels sleepy after sex.

  • gwajo March 15, 2014, 3:54 pm

    I fall fast asleep as soon as come,I even had red bulls and play boosters but nothing helps.
    How can someone refrain from sleeping after the first round? I don’t mind the second one. I’m sure my baby thinks I’m weak because she older than me

  • Todd Wiseman March 17, 2014, 2:57 am

    only a un-educated fooL drink that ”red buLL crap” that level of caffeine is equal to using cocaine, i sure wish the fed government would ban all those fake azz energy caffeine pills , they are allowing a whole new generation of addicts, under the microscope there is very little difference between caffeine and methamphetamine. please drink something healthy , like milk or grape juice, or caf free pepsi cola.

    • josh June 6, 2014, 11:15 pm

      “…something healthy like MILK… pepsi cola.”

      Are you f’ken serious?

  • manny March 30, 2014, 5:58 am

    after 1 orgasm im so tired I can’t move for at least 5 mins

  • TwiceNightly April 29, 2014, 4:19 pm

    This happens to me. I do it with my girl at least twice every time I see her. I’d like to stay awake longer and do it several times more but I’m snoring by midnight. If I see her in the day and need to drive somewhere I’m almost falling asleep at the wheel. Ordinarily if I don’t have sex I have enough energy to be up all night but not when sex is involved. Bain of my existence

  • bowchicawowow May 18, 2014, 1:51 am

    Really irritated at the fact that most articles I find are in regards to “Why MEN” become sleepy after an orgasm. I want TO FALL ASLEEP after an orgasm. Women do it too and to hell with these cultural biases as if to imply that women just want to cuddle and talk after sex. I’m a women who doesn’t want to cuddle and talk after sex. What are we going to talk about the big mystery to the meaning of life? His thoughts don’t need to go beyond the bedroom at that point. If I’m pleased he just served his life purpose. There ya go mystery sovled!

    • GLOOM May 20, 2014, 2:53 pm

      No need to feel irritated… It is scientifically proven that men feel tired after sex… it’s a natural response. Women do not have the same response. Obviously it is possible for women to also feel tired after sex – especially if it lasts awhile and/or they exert a lot of energy. However, just because you feel tired after sex does not mean your body elicits the same biological response as men.

    • Eiad June 4, 2014, 6:17 pm

      Lol angry feminist
      sorry… it’s just funny.

  • Sam Miheso June 22, 2014, 9:34 am

    And for how long is it supposed to take before the 2nd roud? And a normal sex is to last for how long while having sex?

    • Ven June 25, 2014, 2:58 am

      LOL!!! Sex is sex. It depends how strong you are and how you deal with it in action. Actually, men do a lot of work before cumming to his girl/partner. While the girl just needs to adjust to what position suits her as that’s her hobby. They just need to talk and go on

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