There are lots of reasons you might be awake at night, from a racing mind to too much coffee. But a room that doesn’t have the best temperature for sleep is arguably one of the most annoying culprits behind a restless night. No one likes being a hot, sweaty mess or a human ice cube while they try to sleep.
Finding the best temperature for sleep can be tricky, especially if you can’t control the temperature in your room. Ultimately, though, a night spent throwing covers off and then putting them back on doesn’t usually add up to a well-rested morning, so it’s worth a try. And by now, you probably know that sleeping well is the cornerstone for so much of your health. Poor sleep quality is linked to chronic illnesses like depression, heart disease, and type 2 diabetes, according to the Centers for Disease Control and Prevention (CDC). It can also have an impact on our daily functioning and safety, the CDC says.
Clearly, the stakes are kind of high when it comes to sleeping well, and how hot or cold your bedroom is definitely plays a role. Here, we chatted with doctors about the best temperature to help you drift off into dreamland—and stay there.
Why temperature matters for good sleep
Most conversations about how the human body prepares for sleep pinpoint light as the main factor. This is because our circadian rhythm, which dictates our sleep-wake cycle and a bunch of other physiological processes, is governed in part by light, the National Institute of General Medical Sciences says. But the temperature of your surroundings influences this rhythm, too. This is in large part because of how your body temperature factors into the way you power down for sleep, Rajkumar Dasgupta, M.D., assistant professor of clinical medicine and the associate program director of the Sleep Medicine Fellowship at Keck School of Medicine at the University of Southern California, tells SELF.
Dr. Dasgupta offers up a nifty way to think of the relationship between your circadian rhythm and body temperature: “When you [lie] down, your body cools down, and when you wake up, your body warms up,” he says. The general scientific consensus is that your body temperature drops a couple of degrees as you sleep, max. This dip in body temperature may be related to the production and release of melatonin, a hormone produced in your brain that helps with sleep, Dr. Dasgupta says. All of this explains why the National Heart, Lung, and Blood Institute suggests keeping your room “on the cool side” for better sleep, as do many sleep experts.
“In general, keeping a cooler room is helpful because your body’s natural core temperature decreases throughout sleep,” Ajay C. Sampat, M.D., assistant clinical professor of neurology and sleep medicine at the University of California Davis Health, tells SELF. “If you have a cooler environment, that facilitates that transition.”
It’s not just about falling asleep but also staying asleep. As the National Institutes of Health explains, your body temperature is thought to become less regulated during REM sleep (the phase of sleep when you dream, consolidate memories, and more). REM sleep happens multiple times a night, meaning there are various opportunities for the temperature of your room to affect your body temperature more than it usually would. A consistently cool room can help keep your instances of waking up for temperature-related issues to a minimum, Dr. Dasgupta says.