Expert: Dana Krempels, Ph.D. - 8/25/2008

Question
Hi, I don't mean to be rude but can you please tell me if it is true that when men ejaculate and release sperm, they lose energy and it is hard for them to workout in the gym the same or next day? Thank you.

Answer
Dear Alex,

That's not a rude question.  It's perfectly valid, and many people have wondered about this.

It's true that sex and ejaculation require the expenditure of energy.  It is also true that an orgasm causes the release of neurotransmitters, such as serotonin, associated with rest and rumination.  

I do NOT believe it's true that so much energy is expended during sex and ejaculation that a man becomes too weak for athletic activity for a short time afterwards, but it is possible that the neurotransmitters may take the edge off his testosterone levels and make him a bit less aggressive in the gym or on the track.  But that, too, shall pass.  The degree to which this effect is noticeable probably varies a great deal among individuals.

Hope that helps!

Dana