Sleep is vital and mandatory for every human being. During sleep, a person is able to get the rest he/she needs and hence get his/her energy restored and the mind refreshed. This makes the person suitable to be attentive to the next day’s activities.

Sleep also helps a person cope with problems and any strains or pressures associated with work or relationships.Importance of sleep

  The most remarkable help of sleep is seen by sick people who require sleep in order to hasten their recovery.

So, what happens during sleep?
A person is supposed to get both a quality and quantity sleep in order to get rejuvenated. Normally, sleep occurs in natural cycles and a person needs to go through all these stages of the cycle so as to achieve the full benefit of the sleep. If sleep is interrupted and the person has not completed all the stages needed to restore energy and rejuvenate the mind, then the person will wake up with little alertness and unpreparedness to make the best decisions and his/her full capacity to execute normal duties under natural circumstances will be impaired.
When one sleeps, he/she experiences an unconscious state vital for recreational and restoration of his/her body, but the brain remains active. The brain executes body and mind restoration through two states namely:

1. REM (Rapid Eye Movement) consisting of a single stage &
2. NREM (Non-Rapid Eye Movement) which consists of 4 Stages.

The brain cycles naturally between these two stages, with NREM initiating the sleep process followed by a brief duration REM state. When the whole cycle is complete it gets repeated back. A complete cycle normally lasts between 90-110 minutes. During the initial duration of the sleep period, the REM states are relatively short while NREM are long but as the period of sleep progresses the REM states lengthen.
 Non-REM  Sleep State.
It consists of 4 stages which last for about 5-15 minutes each. This sleep state begins when we fall asleep and it takes 75% of the total sleep period.
1. Stage 1– This is the period between being awake and falling asleep. It’s also called light sleep.
During this stage a person drifts from the state of wakefulness to sleepiness. The person can easily be awakened. At this stage many people experience sudden muscle contraction followed by a sensation of falling.
2. Stage 2– At this stage eye movements are reduced and the brain begins resting by slowing waves. The person becomes unaware of what’s happening in the surroundings. The body temperature drops and this marks the onset of sleep. Also the pulse rate lowers.
3. Stage 3 & 4– At these stages deep breathing and body & mind restoration takes place.
The blood pressure lowers down and breathing slows. Muscles are more relaxed hence the blood supply to them increases and moves smoothly. Lost energy is restored while tissue repair & growth occurs. Vital hormones e.g. growth hormones essential for human growth and development of muscles and bone development are released. The immune response system of a person’s body is also strengthened at this stage.

 

 REM sleep state.

This state of sleep amounts to about 25% of the total sleep duration.
At this state the energy needed by the body and mind is restored so as to support and enable the body to be active the following day.
This state is normally characterized by the brain of the sleeping person being active and dreams occur. Eyes dart back and forth and the body becomes still while the pulse rate is restored to normalcy.