Post-sex sleep is very normal; however studies show that men knowledge tiredness and feel need to doze-off after sexual intercourse. Various chemicals and hormones in the body after ejaculation induce sleep and narrows down the chance for men to involve in another round of sexual intercourse.
This is called as love hormone and helps body to relax after sex, making men fall sleep after attaining sexual satisfaction. Oxytocin is a stress busting, relaxation inducing hormone which leads to sleepiness.
This one hormone stiffens the blood vessels and has a crucial role in homeostasis of the body. This hormone is released in the brain and it relaxes the body. Investigate with PET (positron emission technology) scans show that for a man to reach orgasm, the main factor is to do away with fear and anxiety. When this happens, men become relaxed and go to sleep.
After attaining sexual satisfaction releases this hormone, named prolactin that causes drowsiness. If you are looking for ways to block this hormone, get into bed with dopamine is the way to go. Dopamine is a mood booster that decreases prolactin in the body. Now, it has been found that during sleep, prolactin levels are very high in a person. It naturally follows that the release of prolactin causes sleep in men.
Serotonin, Nitric Oxide and Norepinephrine: These are known as the main neurotransmitters, relax the body. The chemical Nitric oxide is released in the penis.
Men usually have more physical exertion while having sex as compared to women. So, men get tired more during sex.
There is another evolutionary and psychological cause of this phenomenon. Since the most basic of male urges is to produce as many progeny as possible for which he needs to re-energise himself as early as possible, sleeping right away is the best way to go about it.
The reasons given above for the tendency of men to sleep after sex are not exact. Actually there a few more biochemical and psychological reasons put forwarded by many health experts on various occasions. None has been able to pinpoint the exact cause of guys’ sleep after sex.