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, a good night sleep occurs in natural cycles and a person needs to go through all stages of the sleep cycle to achieve the full benefit of sleep.
If the sleep cycle 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 stages of the sleep cycle namely:-
REM and Non-Rem Sleep
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 Sleep (nrem sleep) 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 stage of the sleep cycle 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.
Questions and Answers
Many people talk about the circadian rhythm but what is this?
What is biphasic sleep?
Although biphasic sleep sounds a little like a disease, it actually refers to the sleep patterns of Europeans, that include the ‘siesta‘.
So, instead of one block of, typically, 6 – 9 hours of sleep, in a 24 hour cycle, there is an afternoon sleep (siesta) and a night sleep in any given 24 hour period. Interestingly, medical studies, including EEG studies tend to suggest that humans are, by nature, biphasic sleepers.
In addition, there is the polyphasic sleep pattern whereby several sleep intervals are interspersed throughout the 24 hour period.
The idea is to have more quality restorative sleep in the day and hence, more productive time. However, some research studies have shown that this type of sleep pattern may actually be harmful.