Gyroscope Labs / Sleep
Turning off screens before bed
Bright evening screens can delay circadian timing, while effects on actual sleep depend on brightness, duration, daytime light, and what you do on the device.
The idea
Phones, tablets, computers, and televisions can keep the brain engaged close to bedtime. Light from a display can also suppress or delay the evening melatonin signal, especially when the screen is bright and the surrounding room is dim.
Light is only part of the mechanism. A long game, conversation, or video session can displace bedtime even when the display is warm or dim. Turning screens off creates both a darker environment and a clear boundary for the pre-sleep routine.
What the studies show
In a 12-person crossover study, reading a light-emitting e-book for four hours before bed across five evenings suppressed melatonin by 55.12%, delayed melatonin onset by more than 1.5 hours, and increased sleep latency by about 10 minutes versus print.
Chang, Proceedings of the National Academy of Sciences, 2015
Thirteen adults using a tablet at maximum brightness had 3% melatonin suppression after one hour and 22% after two hours, showing that duration changed the biological effect.
In 14 adults exposed to bright light during the day, two hours of tablet reading before bed produced no difference in melatonin or measured sleep compared with a printed book.
Among 58 adults using media at home, longer media sessions were associated with later bedtime and less total sleep, but the percentage of deep and REM sleep did not change.
The circadian light effect is real under controlled conditions, but a screen cutoff does not affect everyone equally. Daytime light, screen intensity, session length, content, and bedtime displacement all matter.
How to do it
- 1Stop using screens and electronic devices at least one hour before bed, every day during the experiment.
- 2Dim the lights in the room and put the devices out of reach so the cutoff is behavioral as well as visual.
- 3Replace the screen session with a paper book or another quiet, screen-free pre-sleep routine.
- 4Keep bedtime steady and track sleep. Do not add blackout curtains or change caffeine timing during the same test.
Evening light and bedtime displacement act that night. Repeat the cutoff across several nights, because one late message or unusually bright day can change the result.
Setup
- Choose a place outside arm's reach of the bed where phones, tablets, and computers will stay overnight.
- Set reminders and alarms before the cutoff so you do not need to reopen a device later.
- Prepare a paper book or another quiet screen-free activity for the first evening.
- Tell frequent contacts about the cutoff and silence nonessential notifications before putting devices away.
Free The experiment uses the devices and offline activities you already have, with no filter or special glasses required.
How hard is it
The setup is free, but the daily effort is high because the cutoff changes entertainment, communication, and often the alarm routine at once. Consistency requires a replacement activity and repeated resistance to checking a device.
Pros and cons
Pros
- Free and requires no wearable or supplement.
- Reduces both display light and bedtime displacement.
- Creates a clear behavioral boundary before sleep.
- Easy to reverse after the comparison period.
Cons
- Can conflict with work, social messages, and entertainment.
- Night mode does not remove stimulating content or time displacement.
- Effects vary with daytime light and display brightness.
- A paper replacement and offline alarm may need advance planning.
Frequently asked questions
Do screens before bed really affect sleep?
They can under sufficiently bright and long evening exposure. In a controlled crossover study, light-emitting e-reader use delayed circadian timing, increased sleep latency, and reduced next-morning alertness compared with print. Chang, Proceedings of the National Academy of Sciences, 2015
Is night mode enough?
Night mode changes the display but does not remove brightness, engaging content, or a delayed bedtime. The controlled e-reader study compared a light-emitting screen with print rather than testing a warm-color setting, so it does not prove that night mode cancels the effect. Chang, Proceedings of the National Academy of Sciences, 2015
Does television count as a screen?
Yes for this experiment. The habit removes phones, computers, tablets, televisions, and other light-emitting displays so screen type does not become another variable.
Can I listen to audio before bed?
Audio can fit the protocol if you start it before the cutoff and do not handle a lit screen afterward. Keep the content and volume consistent so the comparison remains about screen use.
What should I do instead of scrolling?
Prepare a low-effort offline option before the cutoff, such as a paper book, light stretching, or getting ready for the next day. The replacement matters because an empty routine makes checking the device more likely.
What if I need to use a screen once?
Use it when necessary and mark the evening as incomplete. Honest logging is more useful than treating a broken cutoff as equivalent to a completed one.
Measuring whether it works on you
Gyroscope Labs runs the screen cutoff as a tracked experiment against your own baseline. It compares your Sleep Score, HRV, and resting heart rate with the period before the experiment.
Sleep Score is 0–100 and is built from HRV, resting heart rate, and sleep duration, each scored against your own history. Gyroscope also tracks bedtime, so you can check whether the cutoff actually moved sleep earlier.
Reviews from Gyroscope members
Member ratings for this experiment (rating, ease, and effect) will appear here soon.
Test it on yourself
Pick the screen-cutoff habit, run it for a set period, and Gyroscope measures the change in your actual metrics before the experiment versus during it.
- Sleep Score
- HRV
- resting heart rate
- sleep duration
- mood
- energy
- Sleep Score after screen-free evenings vs usual evenings
- sleep duration after completed cutoffs vs broken cutoffs
- energy after paper-reading nights vs screen-reading nights