Written by the Fiveable Content Team โข Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examโขWritten by the Fiveable Content Team โข Last updated September 2025
Definition
Each stage of the five-stage sleep cycle represents a different level of sleep, ranging from light to deep sleep. These stages are characterized by specific brain wave patterns, eye movements, and muscle activity.
Related terms
Stage 1: This is the lightest stage of sleep where you may experience hypnagogic hallucinations or sudden muscle contractions.
Stage 2: In this stage, your brain produces bursts of rapid rhythmic brainwave activity known as sleep spindles.
Stage 3: Also called "deep sleep" or "slow-wave sleep," this is the stage where delta waves dominate and your body repairs itself.
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