The Power Course

Identify the waves in the sleep-wake cycle


1 ) NREM Stage 1
2 ) NREM stage 2
3 ) NREM stage 3
4 ) REM Sleep


Sleep is characterized by NREM and REM phases.NREM is further subdivided into stage 1, stage 2, stage 3,

Sleep starts with NREM stage 1 sleep and followed by Stage 2. Stage 1 and stage 2 are classified as light sleep. This is followed by deep cycle i.e. stage 3.  This is followed by REM sleep.

NREM sleep lasts for 4 to 7 hours and REM sleep lasts for 90 to 120 minutes. Following REM sleep again NREM sleep starts

NREM Stage 1

The transition from awakening to sleep. high amplitude theta waves, slow waves. This stage lasts for 5 to 10 minutes

NREM Stage 2

Body temperature, heart rate, and blood pressure reduction. This stage lasts for 20 minutes.  EEG shows bursts of rapid, rhythmic brain wave activity known as sleep spindles.

NREM Stage 3

Muscle relax, heart rate blood pressure fall. Delta waves are seen in this stage. Less responsive to external stimuli. Bedwetting happens in this stage.


Dreams occur in this stage.

Brain waves are more active similar to the awake stage. This also is called paradoxical sleep, because Muscles become more relaxed. Dreaming occurs due to increased brain activity, but voluntary muscles become immobilized


REM Sleep

Further Reading

Last Modified : 15-Jan-2020

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