Sleep is a naturally occurring phenomenon. It is nature’s call which we cannot refuse to answer. After the day’s hard work, we always come back home exhausted and with strained eyes, muscles, and even a stressed out mind. Though resting goes a long way to help one relax and regain lost energy, it does not replenish and reenergize the body as much as a good night's sleep does.
Before the 1950’s people used to think that sleep was a state of passive unconsciousness. It was believed that when one goes to sleep the bodily functions apart from breathing, circulation, and heartbeat become suspended and never resumes until one wakes up. However, over the years scientists have found out that a lot goes on in our body when we sleep at night. It has been found that our body goes through different cycles and stages when we sleep.
Considering all that happens when we sleep, we are safe to assume that sleep is a periodic and reoccurring state of the mind and body which involves a temporary suspension of consciousness and relaxation of the muscles in which the brain still performs at a lower metabolic rate.
Sleep cycles involve two different parts; Non-Rapid Eye Movement Sleep and Rapid Eye Movement Sleep cycle.
The Five Stages of Sleep
Stage One
It starts from the moment when you nod off or start dozing. Once the sleep sensation hits the body it produces alpha and theta waves which slow down the movement of the eyes. Within this period, which lasts for seven minutes or thereabout, you are still slightly conscious of your environment so that any little thing can wake you up.
Stage Two
During this stage you are still slightly aware of your environment, but not as much as in Stage One. At this stage the brain undergoes some rhythmic brain wave frequency called sleep spindles. There is also a fall in body temperature and reduction in heart rate. This period lasts for 20 minutes.
Stage Three
This is a transitional stage where one goes from light to deep sleep. Delta waves begin to accumulate slowly and one becomes more unaware of his environment and this is the beginning of deep slumber.
Stage One to Stage Three is also called Non-Rapid Eye Movement Sleep.
Stage Four
This is the stage of deep sleep. At this stage it becomes a bit difficult to wake up. It is at this stage that repair of your muscles, growth stimulation, increase of immune function and revitalization of the body takes place.
Stage Five
Rapid Eye Movement Sleep (REM): this stage typically starts about 90 minutes from the time you fall asleep. REM occurs in stages, and each stage lasts about one hour. For every nights sleep we go through five or six REM cycles. In this stage the rapid eye movement starts. You start dreaming, you have increased breathing rate, and increased brain activity. This is the stage where the muscles become paralyzed, or more relaxed. This is also the stage where a scary condition can happen called Sleep Paralysis. People often say that sleep paralysis is a scary feeling because they feel frozen or paralyzed and some people even reported that they felt like they were being choked for a few seconds because your muscles tense up and you wake up before REM is finished.
Sleep Cycles
These stages of sleep are not followed sequentially. It starts from stage one and moves on to stage two, three and four. After stage four the body repeats stages three and two before it goes into REM sleep. After REM, the body reverts to stage two, and the cycle continues. The body goes through the sleep cycle about four or five times throughout a night’s sleep.
Why you need to always sleep for eight hours every night
• We always need to have at least 8 hours of sleep every night. This is because during the stages of sleep, especially REM, the body undergoes some healing processes which help us stay healthy. During the REM phase the mind also gets refreshed and gets over some unpleasant emotions which could have been troubling you. It is at this time that the brain reboots like a computer and comes back to new.
• The immune system is most active in the daytime, but during a good nights sleep, it repairs itself and replaces dead cells. It is therefore important that we sleep well at night for this function to be carried out efficiently.
• Research has also found that sleeping well at night improves insulin sensitivity and helps in fighting diabetes.
• Finally, experts have also found that people who are deprived of a good nights sleep always have problems associated with high cholesterol and high blood pressure.
There are a wide array of benefits associated with having a good nights sleep. Therefore, always sleep well to live a healthy life and to keep the mind and body strong.