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Advanced Sleep Phase

Meaning

Advanced Sleep Phase, or ASP, is a circadian rhythm sleep-wake disorder characterized by a persistent and involuntary tendency to fall asleep and wake up significantly earlier than conventional or socially acceptable times. This physiological shift results in an advanced timing of the major sleep episode relative to the desired clock time. Clinically, individuals with this condition often experience excessive evening sleepiness, finding it difficult to remain awake past their early bedtime, followed by an early morning awakening that can lead to sleep fragmentation if they attempt to sleep later. The condition represents a fundamental misalignment between the internal biological clock and the external 24-hour day.