As modern humans, especially urban populations, become more and more night-lived, people are becoming more and more accustomed to staying up late and going to bed late, as well as getting up as late as possible. Adults such as children and adolescents seem to fall into the same pattern for different reasons: late to bed and late to rise. There are good reasons to oppose such a routine because late bedtimes and late wake-ups have very negative effects on the physical and mental health of children, adolescents and even youth. Humans have retained many behavioral patterns and biological laws that are identical or similar to those of other animals during their long evolutionary history. Among them, the circadian rhythm or “generalized daily rhythm”, which is marked by the sleep and wake cycle, is one of the most important behavioral patterns and biological laws. This pattern of behavior and biology still plays an important role in modern human life and physical and mental health. For most animals, during their evolutionary process, they have gradually developed and passed on some behavioral and activity patterns suitable for survival from generation to generation. As life grows and evolves on the Earth, where the conditions for life in the solar system exist, its various biological traits are imprinted with the laws related to the solar system and the activities of the Earth. For example, the diurnal variation determined by the rotation of the Earth has an important impact on the activities and behaviors of many organisms. These activities and behaviors are both at the external behavioral level, such as sleep and wake cycles, the phenomenon of jet lag in intercontinental travel, and at the internal level, such as growth hormone, adrenocorticotropic hormone and other neuroendocrine circadian rhythm changes, which have corresponding behavioral characteristics. Looking for the survival law of adaptation, this survival law over time will form a certain biological law. For example, humans are still in the primitive stage in order to survive and reproduce, the formation of the sunrise and sunset survival law, while the owl in order to survive must follow the opposite survival law. The long-term existence of such survival laws easily lead to some physiological changes in the organism itself also have to follow certain laws. In the case of humans, the ancient times, the formation of the “sunrise and sunset” habits, requiring people to sleep at night and work during the day. The nerve center that guides people to follow this rule is located in the human brain, mainly the “blue spot nucleus” of the brainstem, which is the main body of the “biological clock” we often say. It is the regulation of this biological clock, so that people are relatively accustomed to their long-established routine, if suddenly changed will not be accustomed to and even sleep disorders and disorders of the waking pattern, intercontinental travel “jet lag” is a specific example of this phenomenon. Since the development of the nervous system and the corresponding development of mental activity are closely related to the process of sleep during the development of the human individual, the adequacy of sleep for children and adolescents in accordance with the physiological requirements plays an important role in the development of their nervous system and mental activity. For example, newborns spend the vast majority of their life in a sleepy state after birth, and it is only with increasing months and age that sleep duration begins to decrease and eventually develop into adult patterns. The age at which children and adolescents spend more time sleeping is precisely the stage at which their nervous system is developing fastest and their mental activity is developing fastest, thus showing the importance of good physiological sleep for them. In the process of understanding the physiology of sleep, a series of regular neuroendocrine changes associated with sleep-wake rhythmic activity have been discovered, for example, the secretion of hormones such as growth hormone and prolactin has a clear diurnal secretion difference. However, more importantly, a hormone has been discovered that is very closely related to the development of the nervous system and mental activity: melatonin. Melatonin is secreted by the pineal gland located in the skull and its secretion level decreases with age, i.e., the younger the individual, the higher the secretion level. In individuals of any age, melatonin secretion follows a cyclical pattern of “daytime low and nighttime high”, i.e., secretion increases after 9 pm, peaks at 2 am, and then decreases rapidly, reaching a minimum level after 10 am (see figure). In the dark environment, melatonin synthesis and secretion increase through complex neuromodulation (impulses from the supraoptic nucleus reach the sympathetic superior cervical ganglion, where postganglionic fibers release norepinephrine, which is then transferred to the signal through β1 receptors, activating the melatonin synthase system), but in the bright environment, melatonin synthesis and secretion increase due to retinal incoming impulses through sympathetic In bright environments, however, the inhibition of melatonin synthesis and secretion is reduced by sympathetic activity due to retinal impulses. So if you sleep late, the total light time is prolonged, melatonin secretion time is shortened, even like “night owls” like people, if you stay up until 2, 3 am, you will miss the peak of melatonin secretion time, the total amount of melatonin secretion is greatly reduced. What are the harmful effects of reduced melatonin secretion on people? Numerous studies conducted by physiologists have found that melatonin has a wide range of physiological effects, including regulation of biological rhythms, regulation of endocrine hormone secretion, regulation of neuroendocrine-immune function, regulation of stress response, and promotion of bone calcium deposition in long bones. The level of melatonin secretion may also affect the aging process, tumorigenesis, etc. Insufficient melatonin secretion level may have multiple adverse effects on free radical damage, elevated blood glucose, sedative, hypnotic, antidepressant, anti-inflammatory, analgesic processes, etc. Moreover, several studies in recent years have reported that melatonin has a modulating effect on mood stability, and that those who sleep normally and secrete higher levels of melatonin secretion have better mood stability. Modern medical research has also developed antidepressant drugs to increase melatonin secretion and enhance melatonin function to treat depression based on the effect of melatonin on mood, which is currently used in clinical practice. This shows that the normal secretion of melatonin has an important impact on human health and mental health. In addition, domestic scholars have also conducted a survey on sleep and learning ability and performance of primary and secondary school students found that the learning ability and performance of primary and secondary school students who slept late or did not get enough sleep were inferior to their peers who slept early and got enough sleep. This indirectly suggests that perhaps the high levels of melatonin induced by good sleep play a role in the academic performance of these students. With this in mind, we strongly urge that getting children to bed early, sleeping well, and getting up early may have a positive effect on their lives.