Is Using Your Phone Before Bed Really That Bad?

Using your phone before bed isn't harmless, but the evidence is more nuanced than most headlines suggest. A controlled study found that reading on a light-emitting screen before sleep delayed sleep compared with reading a printed book, and large surveys link phone use in bed, especially after the lights are off, with worse and shorter sleep. Most of that survey evidence is correlational, though: it shows a link, not proof that the phone is the cause.

Here's what the main studies found, what they can't tell you, and what a sensible middle ground looks like.

What a bright screen does before sleep

The clearest evidence comes from a controlled study published in PNAS in 2015. Researchers compared reading before bed on a light-emitting eReader with reading a printed book. After reading on the screen, participants took longer to fall asleep, had less melatonin, a later body clock and were less alert the next morning than after reading on paper.

That's a clear result, with two limits worth knowing. It was a lab experiment comparing a light-emitting screen with paper, so it tells you about the screen, not about apps. And it didn't test what most people actually do in bed: a fast feed of short videos, messages and news that's designed to keep you going. A phone at night combines both.

Texting and calling after lights out

In a survey of 844 Flemish adults aged 18 to 94, six in ten took their phone into the bedroom. Those who sent texts or made calls after the lights were out reported poorer sleep quality, more insomnia symptoms and more fatigue.

Because this is a survey, it can't show which way the arrow points. Using the phone after lights out might be disturbing sleep. Or people who already sleep badly might pick up the phone because they're lying awake anyway. The study can't separate the two, and it's worth keeping both possibilities in mind before blaming the phone for everything.

Screens in bed and lost sleep

The largest dataset comes from Norway. In a survey of more than 45,000 students aged 18 to 28, each extra hour of screen use after going to bed was associated with 59% higher odds of insomnia symptoms and about 24 minutes less sleep. It was a cross-sectional survey, a single snapshot in time, so it can't prove cause and effect either.

Many people see the same pattern in themselves. In a 2025 survey of 2,007 US adults by the American Academy of Sleep Medicine, 38% said doomscrolling before bed makes their sleep worse, rising to 46% of 18 to 24-year-olds. Half said they use a screen in bed every day, and 26% admitted they prioritise phone time over getting enough sleep. These are people's own impressions rather than measurements, but they say something: plenty of people already suspect their phone is costing them sleep.

What the evidence can and can't tell you

Put together, the picture looks like this:

• From an experiment: reading on a light-emitting screen before bed, instead of paper, delayed sleep and pushed the body clock later.
• From surveys (correlational): people who use screens more in bed, and especially after the lights are off, tend to report worse sleep, more insomnia symptoms and less sleep overall.
• Still open: how much of that link comes from the phone itself, how much from what you do on it (a heated group chat is not a calm audiobook), and how much from poor sleepers reaching for their phones.

There's also a simpler effect that needs no study: time. Twenty minutes of scrolling after you meant to fall asleep is twenty minutes you're not asleep, and your alarm doesn't move to make up for it.

So the honest answer is that a phone in bed won't necessarily ruin your sleep, but the studies point in the same direction, and cutting back is a cheap experiment you can run on yourself.

What to do with this

Health guidance doesn't ask you to give up your phone, only to leave a gap. The CDC recommends turning off electronic devices at least 30 minutes before bedtime and says adults aged 18 to 60 need 7 or more hours of sleep a night. The American Academy of Sleep Medicine suggests powering down at least 30 to 60 minutes before bed.

In practice, that means:

• A buffer before sleep: the last half hour to an hour without a screen, or at least without a feed.
• The phone out of the bed: if it charges out of reach, it's harder to drift into using it after the lights are off.
• Things that end: if you do use your phone in the evening, choose an article or a single episode rather than an endless feed.
• Your own test: try a week with a buffer and notice how long it takes you to fall asleep and how you feel in the morning.

For a step-by-step version, with a cut-off time, an if-then rule and what to do instead, see how to stop scrolling before bed. If you notice that you pick up the phone without really deciding to, why you keep checking your phone explains what's going on.

If the evening scroll is the hard part, a daily limit helps keep it in a box. With Playlock you could give your scroll apps, say, 45 minutes a day. Spend most of it during the day and there's little left for bed, and getting more time means beating a quick mini-game that gets harder with every extra round.

And if you've been sleeping badly for weeks even after putting the phone away, or you feel exhausted during the day, talk to a doctor. Your phone is only one of many things that affect sleep.