Going to bed and waking at steady times turns out to matter independently of how long you sleep. A large wearable-based cohort found irregular sleepers died at noticeably higher rates even among people sleeping adequate hours. One study does not make a law, hence Moderate, but the direction is plausible and the habit is free.
In a prospective UK Biobank analysis of about 88,000 adults wearing accelerometers, sleep regularity predicted mortality more strongly than duration did, with the most irregular quintile at substantially raised risk across cardiovascular and other causes. Mechanisms are speculative so far: circadian disruption touches blood pressure, glucose control and inflammation. Replication in other cohorts would move this grade.
Doing it: Fix your wake-up time first and protect it within about an hour, weekends included. Bedtime can flex a little more. Dim lights and lighter evenings make early nights achievable rather than aspirational.
Who it suits: Especially anyone whose sleep duration looks fine on paper but who feels flat; irregularity is the usual suspect.
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