SCREEN LIGHT
Slower to drop off
In a 2015 sleep-lab study, reading on a light-emitting e-reader before bed meant nearly 10 minutes longer to fall asleep than a printed book.
See the numbersWHAT THE RESEARCH SAYS
Put the phone
to bed first.
The last thing many of us see at night is a screen.
Sleep-lab studies suggest the light from a screen can keep us alert and push the body clock later. NHS advice is simple: put devices away for the last hour, and keep the phone quiet and dark overnight.
Check your bedtime Read the short answer
01 An hour without screens02 Silent and face down03 Paper, not glassSmall changes, easier nights
THE SHORT ANSWER
Screens wake us up,
night mode is not a fix.
Two experiments and the NHS advice
point the same way.
PAPER INSTEAD
Read the old way
The NHS suggests relaxing for at least an hour before bed, for example with a bath or a book, and not using devices right before bed.
Four habits
OVERNIGHT
Silent and face down
NHS Every Mind Matters suggests putting your phone on silent and placing it face down to cut interruptions and light.
Check your bedtimeA QUICK BEDTIME CHECK
What is your phone
doing at bedtime?
Pick the habit closest to yours to see what the research and NHS advice say. The bar shows how much the evidence suggests it may get in the way of sleep.
Based on NHS advice and two published experiments. General information, not personal medical advice.
TWO NUMBERS WORTH KNOWING
Same story,
different book.
Twelve adults read the same way for five nights,
once on a glowing screen and once on paper.
MELATONIN · PNAS 2015
Evening melatonin suppressed by screen reading
≈ 55%
Reading a light-emitting e-reader for about 4 hours before bed suppressed evening melatonin by about 55%. Reading a printed book in the same dim light did not.
FALLING ASLEEP · PNAS 2015
Extra time to fall asleep
≈ 10 min
Participants took nearly 10 minutes longer to fall asleep after the e-reader (25.65 against 15.75 minutes on average), had less REM sleep and felt sleepier the next morning.
This was a small lab study of 12 healthy young adults in very dim room light. The same paper reports a US survey in which 90% of adults used some electronics within an hour of bedtime at least a few nights a week.
FOUR HABITS TO TRY
An easier
last hour.
None of these needs an app. They come from NHS sleep advice and are about what you do with the phone, not which settings you choose.
- Set a screens-off timeAim to stop using phones, tablets and computers about an hour before bed.
- Swap the scroll for a bookRelax for at least an hour before bed, with a bath or a printed book.
- Silent, face down, out of sightPut the phone on silent and face down, and keep clocks out of view.
- Awake after 20 minutes? Get upSit somewhere comfortable and do something relaxing, then go back to bed when sleepy.
WHAT ABOUT NIGHT MODE?
A warmer screen
is still a screen.
Night-mode filters shift the screen towards warmer colours to cut short-wavelength light. In a 2021 randomised trial, 167 university students used their phones for the hour before bed for seven nights with the filter on, with it off, or not at all, and wore wrist trackers to measure sleep.
Across the whole group, there were no significant differences in sleep between the three groups. In those who averaged more than 6.8 hours of sleep a night, the no-phone group had the best sleep efficiency. The authors concluded that night mode did not change sleep outcomes.
QUESTIONS PEOPLE ASK
Frequently asked
Should I stop using my phone before bed?
NHS Every Mind Matters suggests trying not to use phones, tablets or computers for an hour before bed, because the blue light from screens can make it harder to fall asleep.
Does reading on a screen really affect sleep?
In a 2015 lab study of 12 adults, reading on a light-emitting e-reader before bed meant taking nearly 10 minutes longer to fall asleep, less REM sleep and more sleepiness the next morning than reading a printed book.
Does night mode help me sleep?
A 2021 trial with 167 young adults found no significant differences in sleep whether a phone's night-mode filter was on or off, or the phone was not used at all, across the whole group.
Where should my phone go at night?
The NHS suggests putting your phone on silent to avoid interruptions and placing it face down to reduce light, along with keeping clocks out of view.
When should I see a GP about sleep?
The NHS says to see a GP if changing your sleeping habits has not worked, if you have had trouble sleeping for months, or if it is affecting your daily life in a way that makes it hard to cope.
SOURCES
Where the facts come from
Each figure on this page comes from the sources below. Check them for the full detail and context.
- NHS Every Mind Matters: Fall asleep faster and sleep better
- NHS: Insomnia
- Chang et al. (2015), Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness, PNAS
- Duraccio et al. (2021), Does iPhone night shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults? Sleep Health