Don’t be too upset if your partner falls asleep after sex – it might be harder for him (or her) to avoid than previously thought.
Don’t they care? Don’t they enjoy sharing the intimate post-sex moment with me? Was it all too strenuous for the poor thing?
All questions that many have asked themselves silently, while their partner appears blissfully unaware…and asleep.
But as it turns out, there’s a biological mechanism at play, which could be far more powerful than a mental desire to stay awake.
Research explains why men fall asleep
According to French neuroscientist Serge Stoleru, there are clear biological processes which make men sleepy after climax. Using neuroimaging scans, he found that the prefrontal cortex area of the brain reduces in activity after climax.
Being the area of the brain associated with consciousness, information processing and mental activity, it explains why some men can’t help shutting down.
Additionally, two other areas of the brain (the cingulate cortex and amygdala) then stop men from having further sexual thoughts, leading to the refractory period, which is when sexual desire drops significantly.
A potent cocktail of hormones at work
In order to switch off sexual desire, the body releases the hormones oxytocin and serotonin – hormones which are also associated with sleep and relaxation. Serotonin is a precursor to melatonin, which is the hormone that regulates your internal body clock.
In addition, prolactin is released after orgasm, which is another hormone associated with relaxation, satiation and sleep.
Prolactin also mediates the recovery time, as shown by the fact that men with lower levels of prolactin tend to be ready for more sooner.
So there’s a lot going on biologically that makes staying awake not such an easy task. With brain activity associated with consciousness lowering and relaxation hormones flooding the body, falling asleep after sex might simply be a natural process.
There are several other ideas about why men fall asleep after sex, ranging from common sense to evolutionary theories.
For example, it could simply be that sex can be tiring, especially if it involves prolonged and physically exerting behavior.
Muscles depleted of glycogen, intense breathing, and a drop in blood pressure and heart rate might all contribute in some way.
An evolutionary theory is that men may need to rest so they can continue with their drive to produce offspring.
Women, however, may be more likely to want to engage in bonding activities like talking and cuddling to foster long-term commitment.
And another evolutionary theory suggests that men shut down after sex to prevent them from moving on to the next partner. This means they are more likely to remain with the same partner and raise a family.
Do women fall asleep after sex too?
The evidence is conflicting as to whether women do or don’t feel sleepy after sex too. If they don’t fall asleep so easily though, why might this be?
Although some women naturally fall asleep with their partner, there could be a number of possible biological explanations for those that don’t:
1. Women’s bodies don’t release the same combination of hormones associated with relaxation and sleep.
2. Women don’t have the same refractory period as men, often remaining highly aroused even after reaching climax.
3. Women don’t always climax as easily as men do, and therefore any release of the hormones associated with relaxation and sleepiness is less likely to happen.
No difference in how long it takes men and women to fall asleep
According to the scientists Kruger and Hughes, who published a study in in 2011, there isn’t much difference between men and women when it comes to sleeping after sex.
Their online survey of 456 people found that there was “no sex difference in reports of relative sleep onset after having sexual intercourse”.
They do suggest that observational studies would be better than an online survey to measure it more accurately. However, the results show that both men and women believe they fall asleep in roughly the same time period after having sex.
It’s also interesting that the study found that when partners don’t have sex, women tend to fall asleep quicker than men.
Could sex be a natural insomnia cure?
If both men and women’s bodies produce hormones associated with sleep and relaxation, and it affects brain activity, it makes sense that sex might help you sleep.
As for it being an insomnia cure, well, that will probably vary enormously between individuals. But as well as the biological mechanisms at work, there are other ways that sex might influence our sleep:
1. Research has shown that contrary to historical belief, exercise at any time in the day could help you sleep better. So if sex is energetic enough, perhaps it will wear you out.
2. A raised bedroom and body temperature isn’t ideal for falling asleep. In fact, a falling body temperature is preferable. Perhaps then if you do have sex at night, it might be best to try to keep the room cool, or have a refreshing shower before going to sleep.
3. If you don’t experience a climax and therefore the relaxing hormones, could the increased arousal keep you awake?
4. It’s harder to fall asleep when you feel stressed. If sex helps you relax, it might help prevent stress and anxiety from keeping you awake.
If your partner tends to fall asleep straight away after sex, go easy on them and remember that it might just be a little beyond their control.
It might not be so easy for them to fight the potent cocktail of hormones flooding their body, relaxing and shutting them down temporarily.
But if you do find it upsetting, perhaps talk to them about it and encourage them to resist the pull of their biological mechanisms. Tell them you’d like to spend more time cuddling and sharing every intimate moment together.
And the next time someone jokes about men always falling asleep after sex, it’s worth remembering that according to many people, both men and women fall asleep in roughly the same time after all.
Do you find that you naturally fall asleep quickly after sex? Does your partner always fall asleep first, or is there no noticeable difference?
Do you think people should try to resist falling asleep so they can spend quality time together? Feel free to share you views and thoughts in the comments below.