Stages of Sleep
Thanks to sleep studies done over the years we have been able to learn much about what our body and mind goes through while sleeping. Sleep has individual stages that rotate throughout the night in predictable patterns. Feeling well rested and functioning well depends not only the time you spend sleeping but also on how much of the various stages of sleep you obtain nightly.
As you sleep your brain is active and the stages of sleep are linked to distinctive patterns known as brain waves.
There are two basic types of sleep REM (rapid eye movement) and non-REM sleep. When you lay down to go to sleep you typically start with non-REM, which consists of 4 different stages.
Stages of non-REM Sleep
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Stage 1 of non-REM sleep, you sleep lightly and can be awakened easily by disturbances and noises. In this stage your eyes and muscle activity slows.
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Stage 2 of non-REM sleep, your eye movement stops and your brain waves slow showing a distinguishing pattern with sporadic bursts of rapid waves.
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Stage 3 of non-REM sleep, your brain waves become even slower, although they are punctuated by smaller faster waves.
- Stage 4 of non-REM sleep, the brain is mainly producing very slow brain waves.
Stages 3 and 4 represent the deep sleep stages and it is difficult to be awakened. These deep sleep stages are considered to be the “restorative” part of sleep that is essential for feeling well rested and energized the following day.
REM (Rapid Eye Movement) Sleep
REM sleep cycles along the non-REM stages and typically starting 90 minutes after falling asleep. During REM sleep your eyes move rapidly in different directions, breathing becomes rapid, irregular, and shallow and your blood pressure and heart rate increases.
During REM sleep the portion of the brain that handles learning and the laying down of memories is affected. This is also the stage where dreaming takes place. Your leg and arm muscles are temporarily paralyzed so you can’t act out the dreams you are having. Although, REM sleep is very important there is still much to be learned from it to answer the question of “Why?”.
As the night progresses, REM sleep time increases as the time spent in non-REM sleep stages 3 and 4 decreases. By the time you wake in the morning most of your time sleeping is spent in stages 1 and 2 of non-REM sleep and REM sleep. For adults almost half the total time sleeping is spent in stages 1 and 2 of non-REM sleep and one-fifth in deep sleep, stages 3 and 4 and REM sleep.
Next - What Makes A Person Want to Sleep
References: US Department of Health and Human Services
