You want your room to be as dark as possible before you go to bed, Daniel A. Barone, MD, associate medical director of the Weill Cornell Center for Sleep Medicine in New York City, tells SELF. “A little bit of ambient light, whether it be from a streetlight or the sun, can be enough to cause somebody to wake up,” he says.
In fact, being exposed to as little as 10 lux (which is roughly the amount of light you see during twilight hours) before bedtime can have a negative impact on your sleep, Kathryn Jean Reid, PhD, a research professor of neurology (sleep medicine) at Northwestern University’s Feinberg School of Medicine, tells SELF. It’s for that same reason that experts discourage screen use right before bed—TVs, tablets, and phones generate bright, blue light that can make it hard to doze off or snooze soundly through the night. Sure, a few episodes of your comfort Netflix show might lull you into a state of relaxation, but any kind of light exposure before you drift off is going to mess with your sleep.
That’s because the darkness is also helpful when it comes to winding down and getting high-quality rest. Dr. Barone explains that darkness prompts your body to make melatonin, a hormone your brain naturally produces that helps regulate the timing of your sleep-wake cycle. “When you have blackout curtains, what you’re doing is helping promote that [process],” he says.
Blackout curtains will help block light from seeping into your bedroom, so your body’s melatonin production can run its course smoothly and you can get to sleep more easily. Both Dr. Barone and Dr. Reid say that they’re worth a try for just about anyone who wants a dimmer bedroom, with a few caveats. For one, they shouldn’t make your space so cavelike that it’s unsafe for you to get up in the middle of the night (say, to use the bathroom). They also shouldn’t stay closed for too long after you wake up—getting a dose of bright daylight in the morning is just as important for your sleep-wake cycle as keeping things nice and dark at night is, Dr. Reid says. Finally, no blackout curtains will be a cure-all for sleep disorders like insomnia, but a set of light-blocking shades can play a valuable supporting role in an intentional pre-sleep routine.