Social Jetlag

topic

Social jetlag is the circadian misalignment produced by the systematic difference between the sleep-wake timing an individual's biological clock prefers (chronotype-determined) and the sleep-wake timing required by social, work, and school schedules — producing a weekly cycle of circadian shifting that mimics traveling east on weekdays and returning west on weekends, with cumulative health effects (metabolic, cardiovascular, psychological) comparable to chronic mild shift work in affected individuals.

Role

Social jetlag affects an estimated 70% of the population to some degree — with the 30% who are evening chronotypes experiencing the most severe misalignment from morning-optimized social schedules — and is associated in large-scale studies with elevated obesity risk, worse metabolic markers, higher depression rates, and impaired academic performance. Yet it is almost entirely absent from public health conversations about sleep, which focus on duration advice without addressing the timing misalignment that is affecting a majority of the population simultaneously. The policy implication — later school start times for adolescents, flexible work scheduling — represents one of the most evidence-supported and least-implemented public health interventions available.

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