Sleep represents an important aspect of everyone’s life. Adults sleep about 6 to 8 hours a day. Thereby, the episode can be divided into several sleep phases. Restful sleep can play an important role in overall health.
What are sleep phases?
Sleep represents an important aspect of everyone’s life. Adults sleep about 6 to 8 hours a day. Two basic types of sleep exist: REM sleep as well as No-REM sleep. No-REM sleep, in turn, can be divided into further phases. During one night, there are usually four cycles of the sleep phases. The more time spent asleep, the longer the REM episodes. At the same time, these represent the time when people become involved in the most dreams. Thus, sleep is an alternation of different phases. Dream phases are followed by deep sleep, which in turn can be briefly interrupted. In total, an episode lasts about 90 minutes. During this time, people wake up an average of 28 times. However, if the interruption lasts less than 3 minutes, the apparition is not recorded in the memory the next morning. By means of certain medical devices it is possible to monitor sleep and to check in which phase the affected person is. Such examinations are carried out in a sleep laboratory with the help of an EEG. The EEG measures the brain waves and records a completely differentiated image of the nerve activity in the waking state. Some complaints and diseases make a stay in the sleep laboratory inevitable.
Function and task
Sleep serves the recovery of the organism. Thereby, the task spectrum of the nocturnal rest is not completely researched today. However, it is certain that the brain does not rest during sleep. Instead, it is busy processing the impressions, experiences and adventures gathered during the day. In some people, this process is partially expressed in what is dreamed. The brain distinguishes between important and unimportant information. While the relevant ones are stored, it removes the irrelevant thought processes. Such processing is not possible during the day. In order to avoid the development of hallucinations, the brain must be separated from all stimuli, as is the case at night. During the sleep phases, newly learned information is also processed and anchored in the brain, which has a positive effect on the learning effect. Other tasks of sleep include strengthening the immune system, regulating the metabolism, releasing growth hormones and resting the psyche. The deep sleep phases are particularly important for feeling refreshed the next morning. First, however, comes the falling asleep phase. Here, a change in brain waves can be observed. These run longer and slower. However, the falling asleep phase represents the transition, thus sleepers can easily wake up during this episode. The perception of sensory impressions is reduced and the body already begins to relax. There is a general stabilization of heart rate and breathing, muscles lose tension. The first stage of the No-REM phase sometimes occupies only a few minutes. Muscle slackening may cause muscle twitching, often perceived as a falling sensation. In the second stage of the No-REM phase, deeper sleep gradually begins. While the eyes rarely move, brain activity increases. Fewer dreams occur in this phase. If they do make themselves felt, a connection to a real event can often be established. Stage 3 continues the second phase of the no-REM episode and is concluded by the deep sleep phase. In this stage, active regeneration of various structures of the organism takes place. The body is in a state of maximum relaxation. The activities of the brain and eyes are reduced to a low level, breath and heart move regularly. In the deep sleep phase, waking a sleeping person is the most difficult.
Diseases and ailments
With discomfort during falling asleep or sleeping through the night, the majority of Germans have already made acquaintance. Different types of sleep disorders exist. Overall, however, they are manifested by a poor quality of rest at night. Those affected often feel tired, drained and powerless.The ability to concentrate is limited, while irritability often takes on a higher level. The sleep rhythm can be disturbed due to various causes. These include, for example, shift work, depression and other difficult decisions that put a strain on the psyche. Most people with sleep disorders suffer from insomnia (sleeplessness). On the one hand, there are difficulties falling asleep, and on the other hand, sleep is often interrupted by phases in which the affected person is awake. Thus, there is a lack of sleep at the end of the night. Other patients, on the other hand, find sleep early, but spend it very restless and wake up early in the morning. Insomnia is often triggered by lifestyle habits. Here, excessive consumption of coffee and alcohol, cigarettes, certain medications, but also chronic pain, cardiovascular problems, hormonal factors, headaches and thyroid disorders are suspected. Snoring people, on the other hand, often do not notice the interruption of sleep. This leads to breathing pauses, which can result in sleep apnea, a health hazard. Not only the quality of the snorer’s sleep is reduced, but also that of possible fellow human beings. Restless legs, on the other hand, prevent the person from falling asleep due to a movement disorder. Affected persons suffer from a tingling sensation, which is often perceived as unpleasant. In most cases, the discomfort is only alleviated as soon as the patient leaves the bed and movement is initiated. In this way, sleep may be interrupted several times in one night.