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What are the different stages of nonrapid eye movement (NREM) sleep?

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NREM sleep has four levels or stages. Stage 1 sleep, the lightest stage, is the transition from being awake to deeper sleep. Stage 2, intermediate sleep, accounts for 40% to 50% percent of your sleep time. Stages 3 and 4, called slow wave or delta sleep, are the deepest levels and occur mostly in the first third of the night. It is during delta sleep when your body heals itself. It is also difficult to awaken from delta sleep, as most of us feel dazed or groggy.

From: Common Sleep Disorders in Teens WebMD Medical Reference

SOURCES: 

Carskadon M, Rechtshaffen A. in WB Saunders, 1989.  Principles and Practice of Sleep Medicine.

Lewy A, Wehr T, Goodwin F, et al, 1980.  Science,

Walters A, Hickey K, Maltzman J, et al. 1996;  Neurology

National Sleep Foundation.

Hysing, M. , Feb. 2, 2015. BMJ Open

 

Reviewed by Smitha Bhandari on June 11, 2019

SOURCES: 

Carskadon M, Rechtshaffen A. in WB Saunders, 1989.  Principles and Practice of Sleep Medicine.

Lewy A, Wehr T, Goodwin F, et al, 1980.  Science,

Walters A, Hickey K, Maltzman J, et al. 1996;  Neurology

National Sleep Foundation.

Hysing, M. , Feb. 2, 2015. BMJ Open

 

Reviewed by Smitha Bhandari on June 11, 2019

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What are circadian cycles?

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