The practice of setting more alarm clocks in the morning for fear of not being able to get up will easily hurt the body. Human sleep has its own inherent mechanism, natural waking is in line with the law of human biological clock. Early in the morning, the human body to feel the gradual strong sunlight, melatonin secretion will be reduced, serotonin secretion is gradually increased, the metabolism accelerated, people gradually transition from sleep to light sleep, until waking up. If you are suddenly woken up by an alarm clock, the state of stress will cause the body to secrete adrenaline and cortisol, interrupting the sleep cycle, coupled with the repeated ringing of the bell, it is easy to produce panic, depression, feeling of not waking up, and other discomforts. If one is woken up suddenly from deep sleep, one’s short-term memory ability, cognitive ability and even calculation ability will be affected to some extent. Secondly, when a person is repeatedly woken up by an alarm clock, the human body will increase the secretion of adenosine hormone, adenosine level rises will make a person feel more sleepy, it is difficult to fully awake, but will cause sleep pattern disorder. Further, when people are sleeping, the security of the environment is more demanding. Repeated ringing of the bell many times will cause people to wake up from an uneasy, panicky and anxious environment, which is easy to form a deep panic, leading to nervous system disorders, and impulsive and irritable, moody, and slow reaction may also occur. For middle-aged and elderly people suffering from cardiovascular disease, it may also induce heart disease, stroke and other problems.