[Non-photic entrainment of human circadian clock--effects of forced sleep-wake schedule on the circadian rhythm in plasma melatonin].
Non-light cues can reset the human body clock: effects of a fixed sleep-wake schedule on daily melatonin patterns
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Abstract
The forced sleep-wake schedule of 24.0-hour period in dim light condition entrained the circadian rhythms in 3 out of 8 subjects.
- Two hypotheses regarding the human circadian system have been proposed: a two self-sustained oscillator hypothesis and a two process hypothesis.
- The two process hypothesis suggests that sleep or wakefulness does not influence circadian oscillation, while the two oscillator hypothesis allows for mutual interaction.
- Social cues, such as sleep-wake schedules and regular contact with others, are considered significant time cues for the circadian rhythm.
- Bright light (greater than 5,000 lux) has been shown to reset the human circadian rhythm, raising questions about the role of social cues linked to light exposure.
- In extremely dim light conditions (below 5 lux), the forced sleep-wake schedule was also able to entrain circadian rhythms.
- The findings support the idea that non-light factors may influence the human circadian clock, aligning with the two self-sustained oscillator hypothesis.
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