Sleep

Swap the glowing bedtime book

Keep the reading ritual if you like it; change the light source. The cited test did not assess phone night modes.

No costHigh effortSource grade B

AN ACTION TO CONSIDER

Choose a paper book or non-light-emitting reader instead of a glowing screen before bed.

In a lab crossover study, light-emitting eReaders delayed sleep onset by about 10 minutes versus print.

Why consider it?

The same participants used a light-emitting eReader and a printed book under controlled conditions. The comparison is time taken to fall asleep, not total sleep lost. The small laboratory study does not tell us the effect of every phone brightness or everyday screen-use duration.

Read the sources

Source grade B is reproduced from the original work. It does not establish suitability for everyone.

Chang, Aeschbach, Duffy & Czeisler (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS.

Original item: chapter 3, item 8 ↗

Adaptation: Rewritten in English from the locked Chinese original; retained evidence grade and study limits. Effect sizes quoted from the cited source: estimates are kept in their original comparison and population; observational associations are not described as proven personal gains.

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