The time of good dreams is also the time when many diseases are rampant. According to incomplete statistics, nighttime is the highest time of the day for morbidity and mortality, accounting for about 76.1 per cent of total morbidity and mortality. Many diseases are aggravated or attacked at night, and some people who are old and weak or suffer from serious diseases often pass away at night. Why is this so? First of all, because in the daytime, known as the body’s “headquarters” of the cerebral cortex to the excitement of the main, each organ to do its job, are in the best state. At night, the cerebral cortex to inhibit the main organs into a state of rest, which specializes in the management of visceral activities of the vagus nerve will take advantage of the opportunity to make waves. The vagus nerve can make the trachea, bronchial smooth muscle spasm, and make the bronchial mucosal secretions increase, blocking the bronchial tubes, resulting in hypoxia and asthma attacks. Vagus nerve excitation can also cause the coronary arteries that nourish the heart to constrict, resulting in insufficient blood supply, which can lead to angina pectoris or even myocardial infarction. It can also slow down blood flow and cause blood clots to form in the cerebral blood vessels. The vagus nerve will make the peristalsis of the stomach strengthen, the secretion of digestive juices increase, the gallbladder contraction, bile, pancreatic fluid secretion increase, so that colic, gastric ulcers, biliary and pancreatic disorders are prone to attacks. Increased vagus nerve excitability is also the main cause of cough reflex. Secondly, some hormones in the body are secreted periodically, with a certain circadian rhythm, such as adrenocorticotropic hormone, growth hormone, lactogen, pineal gland hormone and so on. This is the biological clock phenomenon. Among them, adrenocorticotropic hormone and adrenocorticotropic hormone, like water and air, are the basic substances to maintain the normal life activities of the human body. Under normal physiological conditions, they have the highest concentration in the early morning when they wake up or start their activities (before 8~9 am), and then gradually decline to the lowest in the middle of the night. Adrenocorticotropic hormone has an important role in human physiological activities. For example, glucocorticoids in adrenocorticotropic hormone can relatively inhibit the utilization of sugar in the muscle, so that the blood glucose increases and maintains the normal physiological function of the human body. In addition, glucocorticoids have a redistributive effect on the body’s immune cells, such as lymphocytes and phagocytes, and are anti-allergic, antitoxic and anti-inflammatory. When the hormone concentration is low at midnight, the above functions cannot be fully realized, then it is not conducive to the control of the disease. In addition, a series of changes will occur in human physiological functions during sleep, such as the sensory function is reduced, the whistle, the heart rate is slowed down, the blood pressure is lowered, the carbon dioxide binding force in the blood rises, the sensitivity of the whoosh center to carbon dioxide is weakened, the lung ventilation is reduced, and the body’s parasympathetic nerves are dominant, and so on. This kind of change, normal people can quickly adapt to, while the patient, the elderly has a certain degree of harm. In summary, it can be seen at midnight, the human body tends to Yang Qi in, those who promote human metabolism, excitement of the hormone plasma concentration is low, so the patient has a certain impact, thus manifesting itself in the night aggravation of the disease. Said people are seriously ill “to heaven” more “choose” in the middle of the night, there is a certain truth.