Is your phone keeping you up at night?

Your phone can keep you up, especially when the screen is bright and close to your face for a long time. That much light can hold back melatonin and push your sleep later ¹. Night mode, the setting that gives your screen a yellow or orange tint, may not fix that on its own ².

The easiest thing you can do tonight is turn your screen down. Next, I'd get the phone out of the bedroom and wake up to a cheap alarm clock instead.

Turn the screen down and keep it short

When you do look at your phone in bed, keep it dim and keep it short. Drag the brightness slider all the way down before you lie down. In a dark room the lowest setting is usually plenty to read by, and it puts a lot less light in your eyes than the screen you use during the day.

Try to hold the phone farther from your face than you normally would, because the closer a screen is, the more of its light reaches your eyes ¹. It also helps to pick a stopping point before you start, like one video or answering the one message you picked it up for. That way a quick check doesn't turn into an hour. I'd leave night mode on if you like how it looks, as long as the brightness comes down too.

The same goes for anything else you're on late. If you're answering work email on a laptop, turn the screen down as far as you can and still read it comfortably. If you're going to be on it right up until bed, a pair of amber glasses is the backup. For watching something in bed, use the TV across the room with its brightness turned down, instead of a phone held up to your face.

Charge your phone in another room

If your phone is your alarm, that's probably why it sleeps next to your bed. Get an alarm clock to take over that job, and charge the phone in the kitchen or the hall. When the phone is next to the bed, it's easy to pick it up to check one thing and look up 90 minutes later. Your alarm still goes off at the same time, so that's 90 minutes less sleep.

A clock by the bed helps in the middle of the night too. If you wake up at 3 and the phone is on the nightstand, you'll pick it up to see the time, and then you see the notifications and the news. A clock tells you the time and that's it, so there's nothing to get pulled into.

Why night mode isn't enough

Night mode warms up the color of the screen, but it leaves the brightness wherever you had it ². In a small study, young adults used a tablet at full brightness for two hours late at night. On its warmest setting, night mode still held back their melatonin ². The researchers thought dimming the screen and spending less time on it may do more than changing the color ².

An hour on your phone before bed may matter less than you'd think. In a study of 167 college students, the ones who spent the hour before bed on their phones every night for a week, with night mode on or off, didn't sleep measurably worse than the ones who stayed off their phones for that hour ³. The students who already slept about 7 hours or more may have slept better without the phone ³. Even so, a quick look at your phone before bed probably isn't what's keeping you up.

How a bright screen pushes your sleep later

The clearest evidence comes from a separate lab study that ran much longer sessions at full brightness. In that one, a small group of healthy young adults read on a tablet for about four hours before bed, five evenings in a row, in a dim lab room. Compared with evenings when they read a printed book, they took about 10 minutes longer to fall asleep, their melatonin rose more than an hour and a half later, and they were less alert the next morning ¹.

Four hours at full brightness is a lot more than a quick look before bed. The tablet also sat on a stand, probably farther from their eyes than a lot of people hold a phone ¹. So the session to cut back is a long one, with a bright phone close to your face in a dark bedroom. A few minutes on a dimmed phone is a much smaller dose than they got.

Why what you're watching matters too

The other thing a screen does is keep your mind going when you should be winding down. It's hard to switch off after a show that ends on a cliffhanger, a game you're trying to win or a work email that gets under your skin. In a survey of young adults, the ones who binge-watched more often, one episode after another, reported worse sleep, more tiredness and more insomnia symptoms ⁴. Ordinary TV watching wasn't linked to any of that. The binge-watchers were also more likely to go to bed with their minds still going, and that seemed to explain the worse sleep ⁴.

So save the new episode or the game for earlier in the evening and decide how many episodes you're watching before you press play. Turn off autoplay too, so the next one doesn't start on its own. Later in the evening, put on something calm or something you've already seen, or step away from the screen for a hot shower.

For the last stretch before you turn out the light, put the screen away and pick up a book under a dim lamp instead.