The human body is the most complex machines in the world, while we know little about it. Many young people feel that they are healthy and no health problems exist. But in fact, in the modem society today, many factors ruin our health , such as the tight rhythm of life, the heavy pressure of work and studying, long-term irregular life, bad diet, poor quality of sleep, lack of physical exercise and etc. Health departs slowly and inadvertently, and we do not realize the physical, physiological and functional changes happen to our body. It always too late to go to the hospital for an examination when we feel there are problems, because we have already missed

the best time for treatment.