Psychiatry and Psychology

Sleep Stages

Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; they formerly included Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep. In 2007, sleep stages were redefined by The American Academy of Sleep Medicine (AASM) as: N1-N2 (sleep onset - light sleep), N3 (SLOW-WAVE SLEEP), and REM SLEEP.

National Library of MedicineMedical Subject Headings2026

Structured Summary

Abstract

Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; they formerly included Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep. In 2007, sleep stages were redefined by The American Academy of Sleep Medicine (AASM) as: N1-N2 (sleep onset - light sleep), N3 (SLOW-WAVE SLEEP), and REM SLEEP.

MeSH Record

Classification

Broader headings

Narrower headings

Related Concepts

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MeSH Record

See Also

MeSH Record

Synonyms

9 entry terms
  • Sleep Stage
  • Stage, Sleep
  • Stages, Sleep
  • N1-Sleep
  • N2-Sleep
  • NREM Stage 1
  • NREM Stage 2
  • N1 Sleep
  • N2 Sleep

MeSH Record

Aspects Covered

5 allowable subheadings

Indexed with the subheadings drug effects, genetics, immunology, physiology, radiation effects.

MeSH Record

History Note

1972 (1969)

MeSH Record

Previous Indexing

  • Sleep (1966-1968)

MeSH Hierarchy

Tree Numbers

  1. F02w.830w.855w.796
  2. G11.561.803w.754

MeSH Record

NLM Classification

WL 108

AMA Style

References

  1. National Library of Medicine. Sleep Stages. Medical Subject Headings (MeSH). 2026. Unique ID D012894. http://id.nlm.nih.gov/mesh/2026/D012894
  2. Sleep Stages. In: Wikidata. https://www.wikidata.org/wiki/Q2237998