Sleep Cycles and How to Wake Up Refreshed
Why timing your alarm around 90-minute cycles can help.
What a cycle is
Sleep moves through light, deep and REM stages in cycles of roughly 90 minutes. Most adults need five or six cycles a night.
Waking between cycles
Waking from deep sleep causes grogginess called sleep inertia. Aligning your alarm with the end of a cycle can make waking easier, though cycle lengths vary by person.
Better sleep habits
Keep a consistent schedule, cool and dark room, and avoid caffeine in the afternoon. Consistency matters more than any single calculation.
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Sleep cycles last about 90 minutes and the plan allows 15 minutes to fall asleep. Waking at the end of a cycle often feels easier.
Educational content only. This article does not replace advice from a qualified health professional. Medical disclaimer.