Sleep Nourishes Life
睡眠滋养生命
Sleep, the chief nourisher in life's feast. — Shakespeare
Sleep is the most important predictor of how long you will live.   — William · Dement, American professor of medical sciences

　　People spend about 1/3 of their life in sleep. Sleep is a fundamental need of life and a vital factor to human health, as important as air, food and water. 　　Sleep helps eliminate fatigue, rest and recharge brain, protect mental health, strengthen immunity; sleep is also important to growth development and longevity and maintain youthful muscles and skin. 　　WHO has included ‘adequate sleep’ as one of human health criteria; however, in China up to 38.2% of the population suffers from sleep disorders, and nearly 100 different types of sleep disorders are threatening human’s health.

Insomnia

Acute insomnia may cause fatigue, dizziness, backache, tinnitus, and short of breath. These symptoms will affect normal life and work. Chronic insomnia may cause irritation, impaired immunity function, and may lead to pathological conditions such as cardiac and cerebral diseases or even cancer.

Sleep-related Breathing Disorders
The most common symptoms are intermittent snoring and frequent apnea during sleep. These symptoms increase the risk of chronic condition. For example, 2.89 times of risks for hypertension, 2.31-8 times for cerebrovascular disease, 1.2-6.9 times for cardiovascular disease and 2.5 times for diabetes. Snoring is directly associated with dementia, arrhythmia and chronic respiratory diseases.
Non-respiratory Diseases-related Somnolence.
Overweight may cause excessive daytime sleepiness. Diabetes is closely related to daytime somnolence. Hypothyroidism is often associated with the symptom of somnolence due to lowered basal metabolic rate. Patients with malnutrition may also present the symptom of somnolence.
Circadian Rhythm Disorders
There is a biological rhythm around 24 hours, which controls the sleep-wake cycles in human. When someone’s habitual schedule is advanced or delayed, or when sleep is deprived, they may start to suffer from sleep disorders like shift work syndrome or jetlag.
Parasomnias
Patients with parasomnias may have unpleasant experience or unintentional behaviors during sleep, or they may undergo certain circumstances that only exists during sleep, for example, arousal confusions, sleepwalk and night terror, which may cause damage to the patients or even the surroundings.
Sleep Movement Disorders
Periodic limb movement in sleep and nocturnal leg muscle cramp, restless leg syndrome, night terror, benign neonatal sleep myoclonus, bruxism and sleep enuresis.
Other Sleep Disorders