[Daily phase adjustment of human sleep-wake cycle].

Bright light is a dominant cue for human circadian systems, with a circadian rhythm period exceeding 24 hours.

• The human circadian system features at least two distinct oscillators with different periods.
• One oscillator has a circadian period of about 25 hours, influencing core body temperature and melatonin rhythms.
• Another oscillator operates with a period longer than 30 hours, affecting the sleep-wake cycle.
• Internal desynchronization occurs when these oscillators free-run with different periods.
• There is evidence of non-photic entrainment, where the sleep-wake cycle aligns with a strict social schedule.

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