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How does sleep work?

Medicine & HealthLesson on requestFree to read

Quick answer

Sleep works as an active, cyclical process where the brain moves through stages — light sleep, deep sleep, and REM (dreaming) — several times a night. During sleep the body repairs itself and the brain consolidates memories and clears waste.

Step by step

  1. The brain cycles through light, deep, and REM stages repeatedly.
  2. Deep sleep restores the body; REM supports memory and mood.
  3. A 'body clock' (circadian rhythm) times sleep using light and hormones.
  4. Too little sleep harms focus, mood, immunity, and health.

People also ask

Why do we sleep?
To repair the body, consolidate memories, regulate mood and hormones, and clear waste from the brain.
What is REM sleep?
A stage with vivid dreaming and high brain activity, important for memory and emotional processing.
What is the circadian rhythm?
Your internal ~24-hour clock that controls when you feel sleepy or awake, guided by light.

Part of the guide: How Your Body Works →