The Science of Sleeping

Sleep is essential for the living bodies. This relaxes our bodies and minds. But all sleeps are not same. You may feel more refreshed even after a 10-minute dozing off than after hours of rolling on bed! Quality of sleep matters more than the quantity of sleep. This happens due to phases of sleeps which are not identical.

Sleep has basically two categories- REM (Rapid Eye Movement) and Non-REM. Sleeping starts in non-REM phase. This category too has stages [1]

  1. Non-REM sleep-
  2. Light Sleep: We are half awake in this stage. Muscles activities start slowing down, twitching may occur.
  3. True sleep: Breathing rate and heartbeat start slowing in this stage. Most part of or sleeping is in this stage.
  4. Deep Sleep: Breathing rate and heartbeat is slowest in this stage. Muscle activities are very limited. If we are woken up right off this stage, we feel disoriented for several minutes.
  • REM sleep- As name suggests, our eyes move rapidly behind the eyelid during this stage. The brain is very active during this stage. This is where most dreams occur. The breathing rate and blood pressure rise during this stage, but the body is paralyzed. This probably is to protect body from acting up on our dreams and hearting itself. People normally do not remember their dreams, but if they get woken off this stage, they may remember some parts.

Normally this cycle goes through step wise. Once completed, the cycle restarts. Normally we have 3-5 REM sleep stages during night. Duration of this stage is longer than previous REM stage. REM sleep is believed to be most important phase for learning and new memories, however newer studies are suggesting Non-REM sleep is more important for these things [2].

How much sleep required?

The need of sleep is for all animals. It’s programmed in our DNA. But how much sleep do we need? Every species have their pattern and requirement. Tigers sleep 16 hours a day while Giraffes can do only with 2 hours.

SpeciesAverage total sleep time per day
Python18 hrs
Tiger15.8 hrs
Cat12.1 hrs
Chimpanzee9.7 hrs
Sheep3.8 hrs
African elephant3.3 hrs
Giraffe1.9 hr

Even across humans different people need different amount of sleep. Different age, gender and phases of lives change our sleep requirement [3].

We cannot evolve or train ourselves to less sleep. Sleep deprivation may even lead a person faster to death than the food deprivation. World record for a man has going without sleep is 11 days. This was set by Randy Gardner in 1965. But just four days into the study he started hallucinating [4].

Impact of technology on sleep patterns

Sleep is such an essential thing, but since the industrial revolution and invention of electricity especially, there have been many tech products which have invaded our personal space- Radio, TV, Phones,  Internet to name a few. And therefore, all such technologies have had an impact on our sleeping pattern. The impact has been getting increasingly severe with the rise of mobile internet. There are hoards of apps which engage our brain and eat into our sleeping time [5].

Human body has a clock like sensor to identify sleep time. This sensor basically reacts to availability of light. As Sun sets off, the body prepares for relaxing. However with our modern technology, the light does not go out at the setting off of the Sun. We have plenty of artificial lights around us. To make things worse, the “screens” emit a blue light which sets off our sensors. Teen-agers are more susceptible to this body-cycle damage due to light than the adults. Mobile also has made us “hypervigilant” as it may start ringing anytime and we do not want to miss. This also impacts the quality of our sleep.


Sleep is an important part of our lives. There is a reason we are designed to sleep almost 25% of our lives. This should not be neglected. Unless completely rested, we cannot work with our full potential- thus hampering our peace of mind and or performance both. As technology is only going to be more and more evolved, we must take necessary steps to get the sleep we need.