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Sleep Cycle

  1. Axel Steiger

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0879

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Steiger, A. 2010. Sleep Cycle. Corsini Encyclopedia of Psychology. 1–2.

Author Information

  1. Max Planck Institute of Psychiatry, Munich, Germany

Publication History

  1. Published Online: 30 JAN 2010


Sleep in mammals, including humans, and in birds has a cyclic structure. Polygraphic recordings (sleep electroencephalogram [EEG]) reveal the alternating occurrence of periods of non-rapid-eye-movement (nonREM) and rapid-eye-movement (REM) sleep. One sleep cycle consists of one nonREM and one REM period. Normal adult human subjects have three to five sleep cycles per night (see Figure 1).