Sleep….it is the common daily routine in everyone’s life…All living organisms need sleep Without sleep no one can live in this earth…Sleep is the sign of rest in the body. As we know about the sleep. When we sleep all our body parts takes rest except our heart. We know about normal sleep but do we know that sleep also consists stages??? And sleep is also different types and what are dreams??as everyone can experience dreams but in which stage does dreams occur and how does the dreams occur and what stages of sleep produce deep rest and how does we are waking up in the morning???? By reading this article, you can clear all the above doubts regarding the sleep. Let’s know the complete information about the sleep stages…As about dreams whole information was given in other article of us “psychology of dreams”…You may clear all your doubts regarding dreams in that article…..Here the information about sleep stages are given….


sleep cycle -


      Usually a complete sleep cycle can take on average 90 to 110 minutes. Each stage lasts about 5 to 15 minutes. Generally, Sleepers pass through four stages of sleep.(1,2,3 and REM sleep) These stages progress from 1 to REM then again begin with stage 1..The sleep cycles start with short period of REM sleep and long period of deep sleep but later, REM sleep lengthen and deep sleep shortens…

Sleep stages:

Usually, sleep is divided into 2 types such as REM sleep and Non REM sleep…REM in the sense Rapid eye movement sleep….In non REM sleep includes the first 3 stages of sleep.whereas other stage is REM sleep Dreams can be experienced in REM sleep…The neurotransmitter which is helpful to maintain good sleep cycle is Serotonin. As after the sleep stages wakefulness occur before and intermittently throughout the various sleep stages or one shifts sleeping position..

Wakefulness is the period when brain activity is highest and muscle tone is active. Let’s know the complete information about various stages of sleep..


      This stage is the lightest stage of Non REM sleep which starts with the slow eye movements. This drowsy stage can be easily disrupted causing awakening. Muscle tone throughout the body relaxes and brain wave activity begins to slow. Occasionally, person can experience hypnic jerks(a brief and sudden involuntary contractions of the muscle which occurs when a person is beginning to fall asleep)…Also the person may experience sensation of falling while drifting in and out of stage 1….

sleep cycle


  Stage 2 is the actual stage of non REM sleep. Awakenings do not occur easily as in stage 1…and slow eye movements discontinued. Brain waves continues to slow with specific bursts of rapid activity known as sleep spindles (these are sudden bursts of oscillatory brain activity generated in reticular nucleus of thalamus)..these are intermixed with sleep structures known as k complexes…Sleep spindles and k complexes are serve as protection for brain from awakening…At this time body temperature decreases and heart rate begins to slow….


       It is also known as deep non-REM sleep. The restorative stage of sleep   consists of delta waves or slow waves of the brain. At this stage awakening is rare and often it is difficult to awake at this stage. Sleep talking(Somniloqy),Sleep walking ,night terrors occur during deepest stage of the sleep…

REM sleep:

        REM sleep is defined as Rapid Eye movement sleep. It is a kind of sleep that occurs at intervals during the night and is characterized by rapid eye movements…Dreaming, body movements, faster pulse and breathing occurs at this stage…

     Thus sleep cycle constitutes all the above four stages..

What is the deep sleep??

      This occurs during the stage-3 of non-REM sleep. Brain waves during this stage is delta waves due to slow speed and large amplitude. Waking a person from this stage is very difficult. Deep sleep reduces sleep drive and produces most restorative stage of sleep. This is why if you take a short nap at afternoon also you still able to sleep at night. During deep sleep Human growth hormone is released  and restores body and muscles from the stresses of the day. Immune system also, restores itself..

When does REM sleep occur:

       An average sleep occurs between 6-8 hours…It is divided in two halves. The first half for most of the people consists stages 2 and 3 with sporadic periods of stage 1 and short REM periods. At night, stage 3 begins to shorten while stages 1 and 2 remain lengthening periods of REM occuring..

A person typically experience three to five REM periods throughout the sleep time with the longest REM period before awakening. In this period, breathing more rapid, irregular and shallow, eyes jerk rapidly and limb muscles are temporarily paralyzed..

Brain waves:                                                     

Stage Wave forms                     


Amplitude(micro volts)           




Pre sleep Alpha rhythm






2. Spindle waves                                                                                                                                           



3.Spindle waves and slow waves








         Hence by reading this article information regarding sleep and sleep cycles can be known by knowing this information, sleep disorders also can be known….

Thanks for reading