C
The mechanism that induces sleep is not known. When it becomes dark, the pineal gland in the brain secretes a hormone called melatonin, which is thought to induce sleep. Exactly why sleep is necessary for good health and efficient mental functioning is unknown. We do know that sleep consists of two very different states: rapid eye movement sleep and non-REM sleep. In REM sleep, dreams occur, the eyes move under the closed lids and there is an increase in oxygen consumption, blood flow and neural activity. REM sleep occurs four or five times during a night.
Beginning periods last about ten to fifteen minutes but the periods get longer as the night goes on. The periods of REM sleep alternate with longer periods of non-REM sleep, when body functions slow. Non-REM sleep has four stages. During the deepest stages it is hard to rouse a sleeper. As the night goes on, the periods of non-REM sleep become progressively lighter.
Sleep in stages 1 and 2 are felt to be restorative as during this time the body repairs itself utilising a hormone called somatostatin. Lack of stage 4 sleep is believed to be important in chronically painful conditions such as fibromyalgia.
D
Healthcare providers diagnose insomnia in several ways. One way is to categorize insomnia by how often it occurs. Another way is to identify the insomnia by what is causing the sleep deprivation. The two main types of insomnia have been described as Primary Insomnia and Secondary Insomnia. Primary Insomnia is a chronic condition with little apparent association with stress or a medical problem. The most common form of primary insomnia is psychophysiological insomnia. Secondary insomnia is caused by symptoms that accompany a medical condition such as anxiety, depression or pain.
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2016-02-26
2016-02-26
2016-02-26
2016-02-26
2016-02-26
2016-02-26