Peer-reviewed study
Bright screens can push sleep later
Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness
Source details
PubMed-linked citation target.
- Authors
- Chang et al.
- Journal
- Proceedings of the National Academy of Sciences. 2015.
- Identifiers
- PMID 25535358 · DOI 10.1073/pnas.1418490112
Claim guardrail
What this page should prevent.
Do not claim all evening screens wreck sleep equally. Frame as light-emitting screen exposure before bed can delay sleep biology.
Geebs coaching takeaway
The study only matters if it changes a behavior.
A shutdown routine is not soft advice; it protects the next day's training quality, hunger control, and decision-making.
Content angles
Safe ways to translate it.
Your nighttime scrolling has a morning cost
Recovery starts before the workout
A bedtime rule beats another motivation quote
Exact answer pages
Questions that cite this source.
Caffeine and sleep answer
Does caffeine before bed hurt sleep?
Caffeine before bed can hurt sleep for enough people that it deserves a real audit, especially if late training, pre-workout, or afternoon coffee keeps showing up before bad sleep. The coaching move is not panic; it is testing timing, dose, and consistency.
Phone and sleep answer
Does using your phone in bed hurt sleep?
Phone use in bed is not neutral for many people. It can keep the brain engaged, expose you to light at the wrong time, and push sleep later. The useful coaching move is not a perfect evening routine; it is getting the phone out of the bed environment first.
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