Mysteries Of Sleep According To Science

“I love sleep. My life has the tendency to fall apart when I’m awake,you know?” Ernest Hemingway

There are three basic stages of consciousness-wakefulness,N REM sleep and REM sleep. There is a profound difference in brainwave patterns during these states.

Brain Wave Patterns

Beta Waves

We have these waves when we are awake. These have highest frequency and lowest amplitude. They vary throughout the day.

Alpha Waves

These waves mark the state when we are awake and relaxed for example during meditation. They are slow, have less amplitude and are less variable. This the most peaceful state.

Theta Waves

They show in N1 and N2 stages of N REM sleep. They are slower than alpha. When we are falling asleep theta waves are detected.

Delta Waves

They show during N3 stage N REM cycle. They are slowest with highest amplitude. This is the period of deepest sleep.

Low voltage random fast waves show in REM cycle.

REM Cycle

It is marked by intense brain activity. Brain waves are fast and random. Breathing is fast irregular and shallow. Eyes move fast in various directions.Limb muscles become temporarily paralysed. In this stage most dreams occur. It follows the N REM sleep.

N REM Cycle

It is characterised by reduction in physiological activities. Brain waves become slow and gain amplitude. Breathing and heart rate become slow. Blood pressure drops. It has three stages.

N1 Cycle

It is a time of drowsiness. Brainwaves and muscle activity slow down.

N2 Cycle

This is a period of light sleep. No eye movements and brain waves become slow , muscles tone and relax. Heart rate is slow and body temperature decreases.

N3 Cycle

It is marked by presence of delta waves, no eye movement and decreased muscle activity. It is very difficult to wake up a person during this stage.

Apart from brain waves there are other changes that make study of sleep exciting and interesting. They are listed below:


Awareness is reduced. We do not use our senses actively. But awareness can be brought back easily. Thus we conserve energy while we sleep.It is a period of rest for brain and body. Healing takes place, new cells are formed,muscles and bones develop.During sickness or physical hurt we recuperate by sleeping longer periods of time.


Body Temperature

It is slightly reduced during N REM cycle. During REM cycle body temperature falls to its lowest.

Respiratory Changes

Breathing is irregular when we are awake, but in N REM cycle breathing rate drops and becomes very regular.In REM cycle breathing rate changes and increases overall.

Heart Rate

Sleep gives heart a chance to rest, heart rate drops.

Physiological Activities

Kidney function slows and production of urine decreases. There is increase in the release of growth hormones.

Cell repair and growth are highest.


These are the least understood and mysterious  feature. Dreams follow illogical and random sequences. Scientists say that dreams are the result of random activity of brain.

Getting more and high quality sleep can improve our health and well being.

” It is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it.” John Steinbeck.





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