Tonight, before you head to bed, check your thermostat. Set it somewhere between 60 and 65 degrees Fahrenheit.
People sleep better in that temperature range. “Not only in terms of maintaining sleep, but also of falling asleep,” says Alon Avidan, MD, MPH, director of the UCLA Sleep Disorders Center. That also goes for how long you sleep and how well.
The exact number is hard to pinpoint. It varies from person to person. But a 5-degree range is easy enough to experiment with.
“You want to make sure your sleep temperature is correct,” says Alberto Rafael Ramos, MD. He’s the research director of the sleep disorders program at the University of Miami Miller School of Medicine.
Once you’ve done that, you need to check a couple of other things in your bedroom to get the temperature just right.
For Kaitie Rudwick, the problem wasn’t as easy to solve as a thermostat set too high. She struggled to get a good night of sleep. The culprit: the heat coming from their memory foam mattress, which she and her husband had had for a few years. Their mattress retained body heat and blasted it back at them.
“We would both wake up sweating in the night,” says Rudwick, who lives in Newberg, OR. “It was so disruptive and uncomfortable.”
No matter what drives up the temperature in your environment, it works against your body’s natural ways to support a solid night’s sleep. Your circadian rhythm, also known as your body clock, lowers your core body temperature by as much as 2 degrees during the night.
That might not sound like a drastic drop. But it’s a strategic shift.
About 2 hours before you head to bed is when this cooling process starts. That’s when you start to feel less alert and likely start to think of sleep.
As your body cools, your pineal gland, located in your brain, releases rising amounts of the hormone melatonin. That, in turn, nudges your body temp to drop. Melatonin helps manage sleep, and its release preps you for slumber.
Your body dips to its lowest core temperature about 2 hours after you turn your lights off. For a good night’s sleep, you’ll want to keep your temperature from climbing back up again before morning. That’s when your body will begin warming naturally, prepping you to wake up.
If that doesn’t happen, your sleep may suffer. Keeping cool, Ramos says, is important for falling asleep and staying that way with only minimal interruptions.
It’s time to rethink this habit.
If you sleep hot, you’re likely to remain in the lighter stages of sleep rather than reach a deeper, more restorative and restful stage, such as what’s called slow-wave sleep, Ramos says. In those light stages, it’s easier for you to wake up.
How hot is too hot? “If someone told me that they slept in a temperature between 70 to 75, I’d say that’s a range that promotes insomnia,” Avidan says. “That’s toasty.”
If you’re used to keeping your bedroom so warm, “Lower the temperature 2 to 3 degrees at a time,” Ramos says. If you get too cold, you can always move it back up a bit. By making little changes up and down with the temperature, most people can find their comfort zone.
Other simple ways to cool things off:
- Open the window to let in cool air.
- Swap heavy blankets for lighter bedding.
- Wear lighter clothes to bed.
Air conditioning and fans help, too, of course. You can point a fan directly at you to amp up the effect of air conditioning.
Another potential source of help: a cooling pillow. Avidan says these use a gel that draws heat away from your head, so that it cools as you sleep.
“These pillows create a temperature drop not in the body but in the head, particularly in the prefrontal cortex,” Avidan says. “When brain temperature is cooler, people can achieve better sleep quality and more slow wave sleep.”
Shop for such pillows at a store rather than online, so you can try them out in order to find one that’s a good fit for you. As Avidan notes, “A pillow’s firmness or how it’s adjusted or aligns with your neck posture is very individual.”
A cooling pillow will only cool you, not anyone else in your bed. Avidan calls that a “lifesaver” for couples with different temperature preferences.
If you like to work out later in the day, do it 3-4 hours before bed and take a hot shower an hour or two after your workout. Why? Your body temperature will go up with exercise and the shower, and then drop later, in your chilled-out bedroom. That contrast is a “very powerful stimulus for melatonin production,” Avidan says.
Rudwick and her husband solved their heat problem by buying a new mattress, made of organic latex and wrapped in wool and cotton, that didn’t hoard heat like the one they retired.
“I feel like a completely different version of myself when I get uninterrupted sleep,” Rudwick says. “When I sleep well, I have the energy, flexibility, creativity, and grace it takes to be present with my family!” Chalk one up for keeping your cool after the lights go out.
