Put glowing screens away an hour before bed; choose paper or an e-ink reader
Reading a light-emitting screen before bed delayed sleep by about 10 minutes, suppressed melatonin by 55%, shifted the body clock over 1.5 hours later and left people sleepier and slower to become alert the next morning.
What it takes
Free. Putting down the phone before bed requires a lasting habit change.
What you may gain
In a laboratory crossover trial, the same participants read on a light-emitting e-reader and on paper. Sleep onset took 25.7 versus 15.8 minutes, about 10 minutes longer. Evening melatonin was suppressed by 55%. Circadian timing shifted over 1.5 hours later, with melatonin onset at 22:31 versus 21:01. Participants were sleepier the next morning and took longer to become fully alert.
Context & considerations
This was a small, tightly controlled laboratory study. Ordinary phone brightness and shorter exposure may produce smaller effects. The study did not test night-mode settings.
Research & references
Chang, Aeschbach, Duffy & Czeisler (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS. https://doi.org/10.1073/pnas.1418490112