Sex and Sleep
There are lots of jokes based on the idea that women want to cuddle after sex but men just fall asleep. So much for the comedy, what’s the reality? Does sex help you sleep? And if so, what’s the science behind it?
Sex sets off a storm of hormonal reactions in the body. Among other things, it decreases the production of cortisol, a stress hormone, and boosts the production of oxytocin, serotonin and prolactin.
Oxytocin is known as the ‘cuddle hormone’ or ‘bonding hormone’ because it’s associated with loving attachment. It’s released in response to social contact, especially skin-to-skin contact with loved ones. Oxytocin helps to reduce blood pressure, lowers stress and provides us with a feeling of calm and relaxation. Serotonin is similar, but goes a step further. This calming hormone helps to relax the body, but it also enables the body to produce melatonin. Melatonin is the hormone that regulates our internal body clock and makes us feel sleepy when night falls.
Prolactin is produced by men when they reach orgasm. This is another ‘relaxation and drowsiness’ hormone. In fact, our prolactin levels rise naturally when we are asleep and studies show that animals become tired when they are injected with prolactin.
There are other factors that tempt us to snooze after sex. First, having sex can be physically tiring. Second, you’re probably having sex in bed or somewhere else reasonably comfortable. Third, sex makes us ‘hot and bothered’. When it’s all over, our bodies cool down and this gradual fall in body temperature stimulates the production of melatonin. More melatonin, more sleepiness.
All in all, it looks like sex and sleep are natural bedfellows. Charmingly, it also looks like this trend isn’t restricted to humans: male rodents also have a tendency for post-coital sleepiness!