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Does using your phone before bed ruin your sleep?

October 20, 2026

"Just five minutes" in bed turns into an hour. You finally put the phone down, and you're wide awake.

Is the phone really to blame? One careful study suggests it plays a real part.

The sleep-lab study

Researchers at Brigham and Women's Hospital in Boston had 12 adults live in a sleep lab for two weeks. On some evenings they read on an iPad for four hours before bed; on others they read a printed book.

After screen reading, people:

• took nearly 10 minutes longer to fall asleep,
• had less melatonin, the hormone that tells your body it's night,
• had their body clock pushed later,
• got less REM sleep,
• felt sleepier and slower to wake up the next morning.

(Chang et al., PNAS, 2015; summary in Medical News Today)

It was a small study in a controlled lab, so real life will differ. But it lines up with a simple idea: bright screens late at night tell your brain it's still daytime.

It's not just the light

Light is only part of the story. A feed also keeps your mind busy: one more video, one more reply. Even with night mode on, an endless feed is built to keep you awake and engaged.

Five fixes that help

1. Charge your phone outside the bedroom. Use a cheap alarm clock instead. This one change removes most late-night scrolling.
2. Set a phone bedtime. An hour before sleep, the phone goes on the charger.
3. Turn on grayscale at night. Most Androids can do this automatically with Bedtime mode in Digital Wellbeing.
4. Silence everything except real emergencies. Let your favourite contacts ring through and mute the rest.
5. Read paper. In the study above, the printed book was the better choice.

How Umer OS helps at night

Umer OS has a Sleep mode: notifications and calls go quiet, important callers still ring, alarms still work, and waking the phone early needs your password. The feeds are blocked all day anyway, so there's nothing to scroll at midnight.

Join the free beta

Related: Dopamine detox: what the science says