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Evening Light Hygiene

Reducing evening blue-light exposure—via dim amber lighting or blue-blocking glasses—improves sleep quality, melatonin secretion, and sleep onset latency.

Light & Sleep

  • Blue light (460 nm) suppresses melatonin 50-80%
  • Light intensity threshold: 30-50 lux
  • Dose-response: longer exposure → greater suppression

Sleep Improvements

  • Sleep efficiency: +5%
  • Insomnia severity: 30% reduction
  • Sleep onset latency: 15 min reduction

Practical Protocol

  • Dim lights 2-3 h before bed
  • Use warm amber (<2200K) lighting in evening
  • Blue-blocking glasses if screen use unavoidable

Pooled evidence (amber / short-wavelength–blocking lenses)

Shechter et al. 2020 (Sleep Advances; PMID 37192881; shechter-2020-blue-light-filtering-sleep-meta) systematically pooled pre-sleep lens trials: headline Hedges’ g estimates include small-to-medium pooled signals for objective sleep efficiency and total sleep time, a large pooled PSQI signal in a small self-report subset, and heterogeneous individual studies overall—read the full text before treating glasses as a guaranteed fix.

Tertiary map

Wikipedia: Melatonin (wikipedia-melatonin-overview) summarizes endogenous melatonin, light suppression, and exogenous supplement threads—orientation only; RCT outcomes on this page stay in the linked PubMed sources. Wikipedia: Sleep hygiene (wikipedia-sleep-hygiene-overview) adds evening routine / bedroom environment vocabulary adjacent to spectral dim-light trials—ISI, melatonin-suppression %, and sleep-onset numbers remain PubMed-first.

Evidence