# Sleep inertia

Sleep inertia is the grogginess and slower thinking just after waking, which usually fades within 15 to 60 minutes.

It is stronger after a short night, when an alarm wakes you from deep sleep, and when you wake at a time your body clock does not expect. Light, movement and a steady wake time reduce it; snoozing tends to make it worse.

Also called: Morning grogginess.

Related: [Sleep cycle](https://revns.com/dictionary/sleep-cycle.md), [Circadian rhythm](https://revns.com/dictionary/circadian-rhythm.md), [Sleep debt](https://revns.com/dictionary/sleep-debt.md)

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