What is sleep?
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Sleep is a natural pattern the body goes through where it enters a different state of consciousness. While it may seem like the body and mind is “turned off” during sleep, there is actually a lot happening.
There are two basic stages of sleep – non-rapid eye movement (non-REM) and REM – in which different actions happen in the body and the brain. Going through the complete cycle of stages takes about 90 to 110 minutes, with most of the night spent in Stages One, Two, Three, and REM sleep. The stages include:
Stage One (nonREM)
this is light sleep, and we can be awakened easily. Muscle activity slows down and the eyes move very slowly as the body relaxes.
Stage Two (nonREM)
our eye movements stop and brain activity slows down.
Stage Three (nonREM)
this is deep sleep and it is very difficult to wake someone up when they reach stage three. There is no eye movement or muscle activity. When someone wakes up during deep sleep, they may feel confused and groggy for several minutes.
during REM sleep, the person’s breathing speeds up and becomes irregular and shallow. Their eyes move around quickly, and the muscles become temporarily paralyzed (they do not move). Heart rates and blood pressure often rise during REM sleep.