Five Stages Of Sleep
Electrical activity in the brain recorded during sleep
1. Light sleep: Muscles relax, body temperature drops, you drift in and out of wakefulness. Fragmented images may appear.
2. Transition: Heart rate, breathing and waves of electrical activity in the brain slow down
3. Deep Sleep: Large, slow waves in the brain.
4. The body becomes harder to awaken as it closes itself off to stimuli. In the fourth stage the waves are similar, but slower.
5. REM(Rapid Eye Movement): Eyes flutter, but the body is paralysed. Heartbeat and blood pressure rise along with brain activity. Dreams appear at this stage.
Source: Dr P.P. Bose, Orthonova Hospital, Delhi