Screens before sleep: how to use Wind down well
What the light does
In a sleep-laboratory study, Anne-Marie Chang and colleagues (2015) found that using a light-emitting device to read before bedtime made it take longer to fall asleep, delayed the body clock, held back melatonin, the hormone that prepares sleep, shifted and shortened REM sleep, and left people less alert the next morning.
It also made people more alert at bedtime, which may tempt them to stay up later. The same paper quotes a survey in which 90 % of American adults used electronics within the hour before bed at least a few nights a week.
Wind down is a screen too
Wind down plays the channel’s calm films from YouTube, and a film is light in your eyes. So use it to stop the day, not to fill the last minutes before sleep.
Turn your screen’s brightness down and switch on its night or warm-colour setting. Keep the timer short, 15 or 30 minutes, and let it end before you go to bed rather than in bed. The page around the film goes dark and the sound fades out, so the end comes by itself.
The usual advice still counts
Sleep hygiene, the habits doctors suggest for mild sleep problems, includes a regular bedtime and a calm hour before it. If you sleep badly for weeks, speak to a doctor: a film cannot fix that.