If you’ve ever shared a bed with a guy, you know that men and women just don’t sleep the same. You might be in sync every waking moment, but when it comes to shut eye, you’re just different. And here’s the scientific explanation of why that is.

1. Women get tired earlier in the evening – Your circadian rhythm is a biological process that controls the body’s sense of when it’s supposed to sleep and wake up. And with women, it signals us to hit the sheets about two hours earlier than it does for men, according to Dr. Diane Boivin, who recently coauthored a study on this subject.
2. Men have more trouble falling asleep early – If you and your sweetie go to bed at the same time, he’s likely to toss and turn while you fall asleep because his sleep cues don’t kick in until later.
3. Women are more likely to wake up before the alarm goes off – Since our circadian rhythms tell us to get to sleep sooner, we’re also naturally more alert earlier in the day. It’s probably why we’re up at the crack of dawn while our partner snoozes away, making up for staying up later.
4. Men dream more than women – Dreaming usually happens when we’re in the deepest phase of sleep, called REM. Being able to fall and stay asleep depends on a bedtime drop in body temperature, and during the second half of a woman’s monthly cycle, her progesterone levels are higher, which makes her body temp rise, especially at night. So women can have more trouble sleeping and get fewer hours of REM sleep in the weeks before our periods, Dr. Boivin says. And all that means we get less time for dreaming – and over the course of a lifetime that really adds up.
5. Women are more prone to having cold feet in bed – According to the experts, the nerves that control blood flow to the hands and feet are more sensitive in women than men, so when our circadian rhythm says it’s time for sleep and our body temp starts to drop, blood vessels constrict to slow the flow of warm blood. Not only does it leave our feet freezing, it also stalls the body’s temperature change and that messes with our ability to fall and stay asleep. And it’s probably why we need to steal the covers too.

Source: Cosmopolitan