This Sleep Foundation guide explains how light is one of the strongest regulators of the circadian rhythm, influencing when we feel alert and when we feel sleepy. It outlines how morning light exposure helps anchor the body clock, while evening exposure, especially from blue‑light‑emitting screens, suppresses melatonin and delays sleep.
The article also provides practical strategies for managing light in the bedroom, including reducing nighttime light pollution and maximising daytime natural light to support healthy sleep patterns.
