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Why do guys get tired after sex?

  1. Oct 11, 2004 #1
    Hey guys;

    I'm wondering why we get tired after sex. I remember reading something in a physiology book about how when you are trying to reach orgasm (i.e., sex) either parasympathetic or sympathetic takes over, but when you have the orgasm the other one takes over.

    Is the taking over of one of those why we get tired?

    Is there any evolutionary reasons for this? Perhaps the sleeping allows you to devote energy into rebuilding your sperm collection, which ensures you of being ready to get more copies of your genes into the next generation. I know you would make the sperm regardless, but perhaps this helps?

    I guess I want to ask this too. How comes sometimes not having sex can keep you awake?
  2. jcsd
  3. Oct 11, 2004 #2
    People get tired after sex? sounds very foreign to me :approve: :biggrin:

    Sometimes it could be stress from work, life or family.
    Last edited: Oct 11, 2004
  4. Oct 11, 2004 #3
    Perhaps they are out of shape, or maybe they have been "out of commission" for a while. :wink:
    I guess it would probably be a case of temporary exhaustion caused by the rush of emotion from the orgasm. Intercourse is a pretty active activity so there will be some physical drainage but I think most of it would be from the emotional aspect. You put everything into achieving the final means and then it all rushes out in a relatively quick period.
  5. Oct 12, 2004 #4
    -- sorry for this post, i was a little inebriated bc i was waiting for my MCAT score lastnight
    Last edited: Oct 12, 2004
  6. Oct 12, 2004 #5


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    Maybe it's psychological. Omni animale post coitum triste, said some Roman.
  7. Oct 12, 2004 #6
    So, how did you do??? Where are you applying to med school?
  8. Oct 13, 2004 #7


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    Tired, or just very relaxed? Orgasm releases endogenous opioids, so to put it simply, you have a bit of a buzz going and are very relaxed, which is conducive to napping.
  9. Oct 13, 2004 #8


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    I don't think that just applies to men :tongue2:
  10. Oct 14, 2004 #9


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    No, it doesn't. They just get a bad reputation for it. :biggrin:
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