According to a survey by the National Sleep Foundation, teenagers actually sleep two hours less than they need every night. This is a problem worthy of parents' attention, because adequate rest at night is very important for restoring energy. Lack of sleep for three weeks or more will weaken children's immune system and make them vulnerable to colds, flu and other infectious diseases. Lack of sleep can also make children irritable, inattentive in class, easily tired and unwilling to exercise or engage in other healthy activities. Many parents think that since children are almost adults, it's no big deal even if they don't get enough sleep. But to achieve the best mental state, teenagers need about 9 hours of sleep every night, 15 minutes, while primary school students need about 10 hours. 4 ways to let children sleep well □ arrange sleep time. Even older teenagers need their parents to urge them to sleep, so that sleep becomes the first demand of children's life. □ Encourage children to take a nap. Tell your child that many successful people will take a nap to replenish energy, and he can also do so, such as taking a nap on his desk after lunch and before class in the afternoon. □ Set an example for children to pay attention to sleep. Arrange enough sleep time every day to ensure adequate rest and set an example for children to live a healthy lifestyle. □ Change the rules. Make and implement a rule that you must finish your homework before surfing the Internet, watching TV or making phone calls every day. Editor's Note: This problem is very common among children in China. Sleep medicine is a new and rapidly developing comprehensive medical science, which not only conducts basic research on sleep, but also mainly discusses and studies the occurrence, development, prevention and treatment of various sleep diseases and their relationship with clinical disciplines. The so-called sleep diseases include two aspects: first, they refer to diseases with disordered sleep, such as insomnia and excessive daytime sleepiness (sleep disorder); The other refers to diseases induced or occurred during sleep, but generally insomnia and daytime sleepiness are not the main complaints. The former is snoring caused by sleep-disordered breathing, while the latter refers to various abnormal involuntary movements and behaviors during sleep, such as sleepwalking and sleep shock. Sleep accounts for 1/3 of life, but people still know little about the basic knowledge of sleep, such as the occurrence and function of sleep, and various sleep diseases are increasing day by day, and the harm is becoming increasingly obvious. For example, according to two survey materials, the number of insomnia patients in the United States is estimated to be as high as 40-60 million, and it is expected to reach 1 billion by the middle of 2 1 century. Domestic survey results show that the prevalence of insomnia is as high as 42%. Lack of sleep leads to the decline of study, work efficiency and production, sick leave, medical expenses and accidents, and its economic losses are difficult to estimate. The space shuttle Challenger tragedy and the three mile island nuclear accident are also related to the lack of sleep of individual staff. As for sleep apnea, it can lead to sleep hypoxia and hemodynamic changes, and then lead to a series of physical diseases such as cardiovascular and cerebrovascular diseases, the incidence rate of which has accounted for 2 ~ 4% of the population, and it is as high as 22 ~ 24% in the elderly population; Just because of traffic accidents caused by daytime sleepiness, the annual economic loss exceeds $50 billion. Since the mid-1970s, developed countries such as Europe and America have attracted more and more attention from the medical community, and various countries have established sleep research institutions. Sleep medicine has become a rapidly developing comprehensive science. For example, there are more than 200 sleep associations in the United States, and there is also a national American Sleep Medicine Association. In the International Classification of Sleep Diseases published by the Sleep Research Association of Europe, South America and Japan, there are more than 80 kinds of sleep diseases.