The Three Stages of NREM Sleep
Non-REM sleep, which is perhaps best defined negatively as any sleep not recognizable as REM sleep, consists of three separate stages (stage1, stage 2 and stage 3), which are followed in order upwards and downwards as sleep cycles progress.
The three stages of NREM sleep are known as:
- Stage 1 (NREM1 or N1)
- Stage 2 (NREM2 or N2)
- Stage 3 (NREM3 or N3)