Here is how to make your bedroom darker for sleep: find where light gets in, then block it. Use blackout curtains or shades on windows, cover glowing gadget lights, seal the gap under the door, and wear a sleep mask for whatever is left. If you need a night light, keep it dim, low and warm-colored.
Light at night can work against your body. In a Northwestern Medicine lab study published in PNAS, researchers compared sleeping in a moderately lit room (100 lux) with sleeping in a dim room (3 lux). After a single night in the lit room, participants' heart rates were higher during sleep and they showed insulin resistance the next morning. Sleep researcher Dr. Phyllis Zee said that just one night of moderate room lighting during sleep can impair glucose and cardiovascular regulation.
That was one night in a lab, so it is not a reason to panic about a streetlight. It is a good reason to make darkness your default. The National Heart, Lung, and Blood Institute (NHLBI) recommends keeping your bedroom quiet, cool and dark, and adds that a dim night light is fine if needed. Mayo Clinic gives the same advice and suggests room-darkening shades. For screens before bed, see blue light and sleep.
At bedtime, turn off every light and close the door.
Lie in bed for a few minutes and let your eyes adjust.
Look for a glow around the curtain edges, above the curtain rod and under the door.
Look for small lights: chargers, TV standby lights, speakers, clocks and routers.
Notice whether your phone lights up with notifications during the night.
Fix the biggest leak first. Often that is the window.
Close the bedroom door and roll a towel along the gap at the bottom.
Turn your phone face down or put it in a drawer.
Unplug chargers and devices you don't need overnight, or turn them to face the wall.
Move your bed so outdoor light doesn't fall on your face. This is one of the Northwestern researchers' own tips.
Turn a bright clock away from you or dim its display.
A sleep mask. The Northwestern team suggests eye masks when you can't control outdoor light.
Small pieces of opaque tape or light-dimming stickers over LED lights on chargers and electronics.
A draft stopper along the bottom of the door.
A dark blanket clipped over the curtain rod, as a quick test before you buy anything bigger.
Blackout curtains. Choose panels wider and taller than the window frame so light can't sneak around the edges.
Blackout liners that hang behind your existing curtains.
Wraparound curtain rods that bring the fabric back to the wall at the sides.
Room-darkening or blackout shades fitted inside the window frame, with curtains layered on top.
Removable blackout window film, which can suit renters (check your lease first).
A valance or pelmet to block the gap above the curtain rod.
Fit: look for an adjustable strap that stays put without pressing hard.
Shape: contoured masks keep fabric off your eyelids, which some people find more comfortable.
Side sleeping: a slim, soft mask is less likely to shift on the pillow.
Care: pick one you can wash, and replace it when the strap stretches out.
A pitch-black room is great until you need the bathroom at 3 a.m. Safety comes first, especially for older adults and children, and you can have both:
The National Institute on Aging (NIA) suggests leaving a light on in the bathroom at night, or using a night light that turns on automatically in the dark.
NIA also suggests putting night lights and light switches close to your bed, keeping a flashlight by the bed in case the power goes out, and using motion-activated plug-in lights for stairs and hallways.
The Northwestern researchers say that if you need a light, keep it dim and close to the floor. Amber or red-orange light is less stimulating than white or blue light, and it should be kept away from the sleeper.
In practice, that means a low, warm, motion-activated light in the hallway or bathroom rather than a bright lamp aimed at the bed. For more on preventing falls at night, see bathroom safety for seniors.
A darker room helps, but it is not a cure for a sleep problem. Mayo Clinic advises contacting your health care provider if you often have trouble sleeping. Also check in if you wake many times a night, feel very sleepy in the day even after a full night in bed, or nod off while driving. For more on night waking, see waking up at night.
This is general information, not medical advice. Talk to your doctor or pharmacist about your own situation.
As dark as you can comfortably make it. NHLBI recommends a dark bedroom and says a dim night light is fine if you need one. In the Northwestern study, the dim comparison room was just 3 lux.
Yes, if you need one for safety. Keep it dim, low to the floor, warm-colored and pointed away from your bed.
If streetlights or early sunrise light up your room, they tackle the biggest light source directly. Mayo Clinic lists room-darkening shades as one way to create a restful room. A sleep mask is the cheaper alternative.
Yes, ideally. NHLBI advises avoiding bright artificial light from a TV or computer screen before bed, and the Northwestern researchers' first tip is not to turn lights on while you sleep.
Sleepward: Bedtime Routine has a gradually darkening wind-down screen, so the last screen you look at before bed gets dimmer instead of brighter. It also offers white, pink and brown noise with a sleep timer, plus an optional wake-up reminder. It is free with optional Pro purchases, has no accounts or ads, and keeps your notes and sleep records on your device.
Get Sleepward free on the App Store
Close the blinds during sleep to protect your health (Northwestern Now)
Sleep Deprivation and Deficiency: Healthy Sleep Habits (NHLBI, NIH)
Preventing Falls at Home: Room by Room (National Institute on Aging)