Sleep–It’s Body Repair Time Series: Part 4 (Understand The Cycles Of Sleep)

By: Dr. Sanjay Kumar Agarwal, Sr. Associate Editor, ICN Group

(In the last article, we knew about what is the correct quantum of sleep. Today, we will know about the cycles of sleep during the night.)

Understand the cycles of sleep

Whether you know it or not, there are different cycles of sleep over a period of 7-8 hours of your sleep. When you understand this mechanism, you will come to know why you were not able to enjoy a good quality sleep earlier. Before you are able to fall asleep, you are awake but at this time, immediately before falling asleep, your mind produces high brain waves, named Beta waves. In this state of mind, we are aligned with our active conscious mind wandering from one thought to another at a rapid pace. 

Our brain is a sort of mini bio-computer which operates on a small amount of electricity. It can process, store & retrieve information and then use that information for taking appropriate decisions. Though, unlike computers, the electric waves generated by the brain do not remain at fixed frequency and keep on changing during the day & night. Sometimes, this frequency is even 20-25 times per second or even more; and sometimes, it drops down to even 1 per second. Researchers & scientists call these vibrations as cycles per second (CPS). Over a period of time, these frequencies have been classified into 4 main categories based on the number of cycles per second:-

  1. Beta is above 14 CPS (mostly about 20 CPS) when your body and mind are active. It mostly represents the waking daytime period. 
  2. Alpha  ranges between 7 to 14 CPS and is associated with light sleep and dreaming. 
  3. Theta ranges between 4 to 7 CPS and is associated with deeper sleep. It is the range where you experience painless surgeries. 
  4. Delta range is below 4 CPS and is associated with deepest levels of restful sleep. 

Researches have revealed that there are 5 stages of sleep. I will not complicate the matter by going deep into sleep mechanics. I will explain in layman language for easy understanding of the sleep cycles. In short, I would say that the last 5th stage of sleep is called the Rapid Eye Movement (REM) stage and first 4 stages are called non-REM (NREM) stages. These four stages also include two sets of light sleep (stage 1 & 2) and deep sleep (stage 3 & 4). After passing through earlier 4 stages, you enter into your first REM sleep period, which lasts about 15-20 minutes only. Then again cycle of 4 stages of NREM and REM sleep is followed. This alternating pattern continues throughout the night but with the progress of the night, deep sleep periods become shorter and REM sleep period tend to grow longer. 

When we enter deep sleep, our blood pressure, respiration rate and heart beat reaches at their lowest levels during the day. This is the most important part of sleep cycle, during which our body recharges itself most and various body parts get repaired to get rid of body fatigue, accumulated during the day. 

 Researches have also revealed that:-

  • The period of deep sleep is longest in the first sleep cycle and keep on getting shorter over next sleep cycles.
  • The period of REM sleep during first sleep cycle is shortest and keeps on increasing over next sleep cycles. 

Here you can easily understand that during 1st deep sleep phase, your body needs most recharging, therefore, the period of deep sleep is longest during first sleep cycle. In the 2nd cycle, the body is already relaxed than compared to start of first sleep cycle, therefore time taken for completion of 2nd phase of deep sleep is comparatively lower; and the gradual reduction in deep sleep period is continued. 

This would automatically mean that after completion of 3 or 4 cycles, if we choose to sleep for one more cycle, it would be a practical waste of time, as we will get benefit of deep sleep for very less time.   

It is most difficult for us to awake during REM sleep period by external stimulation. That is the main reason, why we feel drowsy if we wake up at the alarm’s bell or by any family member like mother or spouse or by any other sound. If you could understand this, you will be able to understand the importance of getting awake as per your internal body clock. If you are awake, when you have just finished the sleep cycle ending with REM sleep, you will feel fresh and energetic for remaining day. 

I believe, now you can easily understand that 3 complete cycles of sleep are more beneficial for you in comparison to 3.5 or 3.6 or even 3.9 cycles of sleep. You can see that as the period of deep sleep reduces from cycle to cycle, there is practically no need to have an extra cycle after your body is refurbished internally during first 3 or 4 cycles. 

In my workshops, people ask me what is the time of completion of one cycle of 5 stages of sleep. 

My answer is that it varies from one person to another, depending upon various internal & external factors; though normally it takes about 1 to 2.5 hours. So, you are not in a position to decide, when you will be at the end of your 3rd or 4th sleep cycle. Still, rest assured, if you allow your body to adapt to regular sleep patterns over a period of about one month or so, your inner body clock will tell you the exact waking up time and you will not require any external stimuli for waking up like alarm etc. 

[In the next article, we will know about the body’s internal sleep clock. So, stay tuned to improve your sleep patterns.]

Dr. Sanjay Kumar Agarwal, Creator & trademark holder of the concept G.O.P.T.A.®  is an Author, Growth Accelerator Coach, GOPTA NLP Trainer and Strategic Interventionist. ( He is recipient of Honorary Doctorate of Excellence (Management) by prestigious Young Scientist University, California, USA. He is creator of ‘Ethical Mind Influence’ program for growth & success ( ). He is Founder of ‘International GOPTA NLP Academy’ and is popularly known among his fans & followers across the globe as ‘Time and Goal Guru’.

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