Sleep Cycles Explained Simply

June 13, 2020

Sleep Cycles Explained Simpy 

Sleep cycles are the progression through the various stages of NREM (non-rapid eye movement) to REM (rapid eye movement) sleep, we go through each night while sleeping before beginning the cycle again. An entire sleep cycle lasts between 90 -120 minutes. The average person goes through all 4 sleep cycles 3-5 times per night. Once you go through all four stages once, you repeat the process, again, so on and so forth until you wake up. Here are all 4 sleep cycles explained simply. 

Sleep Cycles Explained Simpy

• There are 4 stages of sleep. The first 3 stages of sleep makeup NREM (non-rapid eye movement) and the last stage of sleep is REM (rapid-eye movement).
• An entire sleep cycle lasts for approximately 90-120 minutes and the average person goes through all 4 stages 3-5 times per night.

Stage 1

Stage 1 is the beginning of the sleep cycle and is the shallowest stage of sleep. During this stage, the brain produces alpha and theta waves which is often associated with relaxation. Sudden muscle jerks can occur in this sleep cycle. Stage 1 is very short, typically lasting between five to ten minutes. 

Stage 2

Stage 2 is the first actual stage of defined NREM sleep. During this stage, your heart rate begins to drop and so does your body temperature. There is also an increase in theta wave frequency and k complexes. Theta wave activity is classified as slow brain-wave activity and is often associated with creativity, daydreams, and is a repository for memories and emotions. According to the American Sleep Foundation, people spend approximately 50% of their sleep in this stage. 

Stage 3

Stage 3 is the most restorative stage of sleep and is the beginning of deep sleep. There are no muscle or eye movements in this stage. During stage 3 your body temperature drops, blood pressure falls, breathing slows, and your body begins to repair muscle and tissues. This sleep cycle can typically last between 45 to 90 minutes and is difficult to wake someone up while they are in this stage of sleep.

REM

REM is the longest stage of sleep and is also the stage where most of our dreaming occurs. During REM sleep your heart rate and blood pressure increase and your breathing is faster. Brain waves are also more active during this stage and as Jeffrey Lliff, Ph.D., assistant professor at Oregon Health and Science University said, "on brain scans, REM sleep looks a lot like being awake." The American Sleep Foundation estimates that people spend approximately 20% of their total sleep time in this stage. 

Sleep Cycles Explained Simply Recap 

A sleep cycle is a progression through the various stages of NREM (non-rapid eye movement) sleep to REM (rapid eye movement) sleep, before beginning the cycle again. An entire sleep cycle lasts approximately 90 - 120 minutes. The average person goes through all 4 stages 3-5 times per night. Once you go through all four stages once, you repeat the process again, so on and so forth until you wake up. It is important to go through each sleep cycle multiple times in order to give your body and brain an ample amount of recovery time. 

Overall 

• There are 4 stages of sleep.
• The first 3 stages makeup NREM (non-rapid eye movement) and the last sleep cycle is REM (rapid-eye movement) sleep.
• An entire sleep cycle lasts for 90 - 120 minutes.
• The average person goes through all 4 stages 3-5 times per night.

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