Research
Adherence
Light exposure at specific times (dusk/dawn) resets the central SCN clock by inducing Per1/Per2 gene expression, with the direction of the shift (advance vs. delay) depending on the timing of light exposure.
View bright light in the morning to advance your clock (wake up earlier) and avoid bright light in the evening to prevent delays (stay up later). This leverages your biology to align your sleep with your schedule.
StrongSupportsVERY_HIGH confidence
This model therefore provides a molecular explanation for the differential resetting actions of dusk (delay) and dawn (advance) light on circadian behavioural and physiological rhythms.
Why this rating
Well-established molecular mechanism with clear experimental support.
Source
Circadian clocks: regulators of endocrine and metabolic rhythms
Michael H. Hastings et al. · Journal of Endocrinology · 2007
DOI 10.1677/joe-07-0378
narrative_reviewCited 422×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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