Why Men Get Sleepy After Sex (and Why Women Shouldn't Take it Personally)
Immediately after a man has an orgasm, he's likely to become drowsy. Although some women may find they also often feel sleepy after sex, it's a phenomenon that's typically more pronounced in men. The fact that men often get sleepy after sex constitutes one of the many differences in the male versus the female sexual response cycle.
Because a female partner has a different sexual response cycle than her male partner, she may not really understand why it is he gets sleepy after making love. After sex, she may be in the mood for cuddling or pillow talk, but he might be too sleepy to take much notice. She may interpret the sleepiness as sudden disinterest. However, this isn't really what's going on. Rather, there are many complex chemical reactions going on in his body after orgasm that explain this.
Sleepy After Sex? Prolactin Is Largely Responsible
Men secrete much more of the hormone prolactin after orgasm than women do. One of the major roles of this hormone is to "switch off" sexual arousal. The presence of prolactin keeps the man from getting aroused again, creating what is called the refractory period. After orgasm, he won't be capable of another round of sex until the prolactin levels decrease again. By contrast, women tend to return to a "semi-aroused" state due to lower prolactin levels than men, explaining why many more women than men are capable of experiencing multiple orgasms in one session.
The older a man gets, the more prolactin will be released after sex and thus the longer his refractory period will be. When a man is in his early 20s, his refractory period may be as short as three minutes, yet once he is in his 60s it can take as long as 24 hours.
Prolactin also has effects other than putting an end to arousal. It produces an emotion of sexual satisfaction and has the side effect of drowsiness. Prolactin's role in sleepiness is demonstrated by the facts that prolactin levels are higher when a person is asleep and that animals injected with a dose of prolactin instantly become tired. Since younger men's prolactin spikes are much more short-lived, older men are more likely to be sleepy after sex.
Interestingly, only partnered sex really produces noticeable amounts of prolactin afterward. For unknown reasons, an orgasm due to masturbating only produces one-quarter the amount of prolactin.
Other Contributing Factors
Although prolactin plays one of the biggest roles in why men get sleepy after sex, there are still many other contributing reasons. The nature of sex itself and the way it fits into our lives can influence a man getting sleepy afterward. Many people tend to have sex with their partners at night, in a quiet room and on a comfortable bed. Naturally, this makes it seem very inviting to fall asleep after sex. The physical exhaustion caused by sex also makes a difference, especially since many of the most popular sex positions place the man in the more active role.
Another reason is simply that sex is very relaxing due to the action of the parasympathetic nervous system. A prerequisite to having an orgasm is to be very relaxed, with no traces of fear or worry present in your brain. If you've achieved orgasm, it means you're very relaxed. This relaxation doesn't go away immediately after sex ends, thus promoting post-sex drowsiness.
Aside from prolactin, a large number of other hormones fluctuate after orgasm that also influences whether someone gets sleepy afterward. The hormone cortisol, which is known as the "stress hormone" decreases, lowering stress and promoting relaxation. Oxytocin and vasopressin are released after orgasm, which has the side effect of drowsiness. The neurotransmitter serotonin is released in the brain, giving a calming effect, while the action of the stimulating neurotransmitters epinephrine and dopamine is reduced. This complex cocktail of hormone changes is what is ultimately responsible for men falling asleep after sex.
Drowsiness After Sex in a Nutshell
When your male partner falls asleep right after sex, it's not because he's suddenly disinterested or because he doesn't care to talk to you anymore after the act. This phenomenon is really due to many complex physiological processes that are beyond his control.
It's best to simply give in to feelings of drowsiness after sex. The sleepiness is natural, conducive to a good night's sleep and simply feels good. This makes just before bedtime an optimal time to have sex. If you want to have sex during the day, consider also making time for a short nap afterward.
However, if you really don't want to deal with post-coital drowsiness, you don't have to. After sex, enjoy a food or drink that is known to produce a spike in dopamine. Since dopamine is a stimulatory neurotransmitter, increasing it will help to cancel out the other chemicals that are making you sleepy. The best examples of foods and beverages to increase dopamine are chocolate and coffee. Eating chocolate increases dopamine and serotonin. The caffeine in coffee increases dopamine and the other stimulating effects of caffeine will provide even more of a boost.