Stages of sleep

Stages of sleep

Introduction

Sleep is a state of decreased consciousness and physical activity of the body. Researchers used electroencephalographs (EEGs) to track the brain waves, and recognized that the sleep cycle has two phases (six stages) during sleep. These phases are:

Non rapid eye movement (NREM)

Stages 1 through 4 are characterized as NREM sleep. Stage 0 (5 % of sleep), is when a person becomes drowsy and drifts to sleep. Stage 1 is when person loses his response to stimuli. It shows lower frequency waves. During stage 2 (45-55% of sleep), brain spindles, or fast frequency brainwaves appear. Stage 3 ...