The 5 Stages Of Sleep
Stage 1 Sleep
During stage 1, which comprises light sleep, you drift in and out of sleep and can be awakened easily. Your eyes move very slowly and muscle activity begins to slow.
If awakened during stage 1 sleep you will often remember only fragmented visual images. You may also experience sudden muscle contractions, often preceded by a sensation of starting to fall. These sudden movements appear similar to the jump you make when startled.
Stage 2 Sleep
When you enter stage 2, which accounts for about half of your total sleep time, your eye movements stop and your brain waves become slower, with occasional bursts of rapid waves.
Stage 3 Sleep
In stage 3, extremely slow brain waves, called delta waves, begin to appear, interspersed with smaller, faster waves.
Stage 4 Sleep
In stage 4, the brain produces mainly delta waves and there is no eye movement or muscle activity.
It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. If awakened during deep sleep you do not adjust immediately and often feel groggy and disoriented for several minutes after you wake up.
Stage 5 (REM) Sleep
The final stage in the sleep cycle is called REM (Rapid Eye Movement) sleep.
During this stage your breathing becomes more rapid, irregular, and shallow; your eyes jerk rapidly in various directions; and your limb muscles become temporarily paralyzed. Your heart rate increases, your blood pressure rises, and, if you're male, you may develop a penile erection. If you awaken during REM sleep, you will often remember bizarre and illogical tales - dreams.
The first period of REM sleep usually occurs about 60 to 90 minutes after you fall asleep. A complete sleep cycle takes 90 to 120 minutes on average.
The first couple of sleep cycles each night contain relatively short REM periods and long periods of deep sleep. As the night progresses, REM sleep periods increase in length while deep sleep periods decrease. By morning, you spend nearly all of your sleep time in stages 1, 2, and REM.
Next >>> How much sleep do you need?
The information contained here should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only and in no way should be considered as an offering of medical advice.
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