What is really happening to your body when you are sleeping?  We have all heard of a REM cycle, but what is it and how do have more of them?  Let’s dive right in! There are at least 4 different stages of sleep that our bodies enter throughout the night and they each provide something different for our bodies.  Let’s break them down individually to see what is happening.


Stage 1– think of this as a transitional phase.  You aren’t quite awake, but you aren’t quite asleep either.  It’s that feeling of drifting out of consciousness that eventually leads to a light sleep.  At this point in sleep you may experience muscles jerking, with enough force it can wake you right back up.  This feeling of being jolted awake is called hypnic myoclonia. It is very normal and nothing to be concerned about.

Stage 2– approximately half the time we spend sleeping is in stage 2.  This phase is all about slowing things down. Brain waves slow, eye movement stops, heart rate drops and body temperature decreases.  However, the body still finds rhythm with occasional bursts of brain wave activity and a rolling pattern of muscle tone followed by muscle relaxation.

Stage 3– this is what is known as deep sleep.  It is hardest to wake up at this point and if you do grogginess and being disoriented are common feelings.  Often this stage is called slow wave sleep, it is still non-REM sleep but here you are restoring and healing your body.  The brain wave activity is very slow and rhythmic, breath is even and deep, the body and eyes are immobile. At this point in sleep your body is releasing hormones for appetite control, so you don’t wake up hungry and growth hormones to repair damaged tissues.

Stage 4– now we finally make it to REM sleep, which stands for rapid eye movement.  Quite the opposite of the other stages of sleep here your brain waves pick up again and are bursting with activity.  In a normal night of sleep this is what you are doing 20% of the time (though in babies it can be up to half). Though your body is paralyzed your eyes are darting and moving in every direction.  Even though you are sleeping your brain acts like it is awake. Your blood pressure and temperature begin to rise, and your breathing starts to get faster and shallower. This is also where most of dreaming occurs.  This stage is extremely important for revitalizing the brain and allows you to be sharp and focused throughout the next day. At the end of a REM cycle your body is closest to being awake.


A sleep cycle refers to progressing through each of these stages, which takes approximately two hours.  In a typical night of sleep a person will have about 4-5 of these cycles. When you wake often, have sleep apnea, or insomnia your body doesn’t get the rest it needs to recuperate, heal and prepare for the next day.  Now that you know a little more about what your body is doing during sleep you know how important it is to your health to get tucked in and get your 8 hours!

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