Evening light reduction
Dim overhead lights two hours before bed; switch to warm bulbs and screen blockers.
Why
Evening exposure to bright (especially blue-spectrum) light suppresses melatonin release and pushes back the body's natural sleep-onset window. Reducing intensity and shifting colour temperature in the two hours before bed restores normal melatonin timing.
Slot in your day
How to do it
How
Dim overheads after sunset. Use warm-white (2700K or below) bulbs. Set screens to night-shift mode. Consider blue-blocking glasses if screens are unavoidable.
Sticking with it
Switching one main lamp to a 2700K bulb is more durable than relying on settings toggles each night.
Evidence
Gooley 2011 J Clin Endocrinol Metab (n=116, ages 18–30): room-level light before bed suppressed evening melatonin and delayed melatonin onset in 99% of participants, shortening melatonin duration by ~90 min. Chang 2015 PNAS replicated this with eReader use: ~55% melatonin suppression and a phase delay vs. paper reading.