#The scientific reason why so many men fall asleep after sex

Picture this, you’ve just had a great session beneath the sheets and then you hear a snoring sound.

If this is familiar then you’re not alone – as many men fall asleep after having sex.

But before you start berating your boyfriend for his bedside manner, there is actually a scientific reason for his immediate snoozing.

In both men and women, sexual stimulation has been proven to boost brain activity.

When we have sex we tend to be relaxed and in turn, we release a lot of stress and anxiety that may have been building up throughout the day.

Research using positron emission tomography (PET) scans has previously proven this – and it’s known that when we are relaxed and have released stress, it’s easier to fall to sleep.

But when looking at why men seem to fall asleep faster, it’s actually due to a cocktail of chemicals released when they ejaculate.

These include norepinephrine, serotonin, oxytocin, vasopressin, nitric oxide (NO), and the hormone prolactin.

It’s the release of prolactin that makes a particular difference as this is linked to the feeling of sexual satisfaction, experts say.

It also helps mediate the recovery time, in other words, how long a man has to wait before going in for round two.

Men deficient in this hormone can sometimes also have faster recovery times.

Experts at New York University’s Science, Health and Environmental Reporting Program explained: “Prolactin levels are naturally higher during sleep, and animals injected with the chemical become tired immediately.

“This suggests a strong link between prolactin and sleep, so it’s likely that the hormone’s release during orgasm causes men to feel sleepy.

“Prolactin also explains why men are sleepier after intercourse than after masturbation.

“For unknown reasons, intercourse orgasms release four times more prolactin than masturbatory orgasms”.

IMPROVED SLEEP

Two other chemicals released during sex include Oxytocin and vasopressin.

The release of them usually accompanies melatonin – which regulates our body clocks.

Oxytocin has also been proven to reduce stress levels which could lead to sleepiness and relaxation.

Max Kirsten resident sleep expert at Innermost and The Sleep Coach said having sex also actually improves our sleep quality after the event.

He explained: “We release an important intimacy hormone called oxytocin, which naturally reduces our stress cortisol levels dramatically. 

“Having an orgasm will help you fall asleep because it releases the hormone prolactin that makes you feel relaxed and very sleepy.

This story originally appeared on The Sun and has been reproduced here with permission.