Sleep is essential to the well being of every human being. During sleep, a person gets the rest they need and their energy levels restored, their bodies repaired and the mind refreshed.
Sleep helps a person cope with the daily activities, strains and stresses of everyday life.
Sleep also helps a person cope with emotional problems; including pressures associated with work or relationships.
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.
What happens during sleep?
Each person needs a certain amount of both quality and quantity of sleep in order to be rejuvenated. Normally, sleep occurs in natural cycles and a person needs to go through all stages of the cycle to achieve the full benefit of sleep.
If sleep is interrupted and a person has not completed all of the stages of sleep needed to restore and rejuvenate the body and mind, then this can affect levels of alertness, decision making and the capacity to execute normal duties under natural circumstances.
When a person sleeps, he/she experiences an unconscious state vital for restoration of the body, but the brain remains active. The brain executes body and mind restoration through two states namely:
1. REM (Rapid Eye Movement) This consists of a single stage. As the title suggests this stage is characterized by the eyes rapidly moving in all directions under the closed lids. Most dreaming appears to take place during this stage.
2. Non-REM (Non-Rapid Eye Movement) This part of sleep consists of 4 Stages. The Non-Rem stage of sleep is necessary before the REM stage can take place. It consists of three stages characterized by increasingly deep levels of sleep.
The brain cycles naturally between these two stages, with NREM initiating the sleep process followed by a brief duration of REM stage sleep. When the whole cycle is complete it is repeated. 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.
REM sleep state.
This state of sleep amounts to about 25% of the total sleep duration. In 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 becoming active and dreaming will occur. Eyes dart back and forth behind the lids and the body (normally) is very still and deeply relaxed.