We often say: life is exercise. Exercise is necessary for a healthy body, but the problem is to grasp the “amount” and “degree” of exercise. Just like eating, people can not survive without eating, to eat enough to eat well, in order to protect the nutrients needed for muscle metabolism, but if you eat too much, overeating, will eat bad gastrointestinal tract, but also the modern rich disease “three high” (high blood sugar, high blood pressure, high blood pressure) and obesity. In our daily life, our activities are completed by the movement of the joints. There is a layer of smooth cartilage on the joint surface called articular cartilage, which can reduce the friction between the two bones during activities and cushion the shock and impact. However, as we age, the cartilage in the joints will wear to varying degrees, and when the wear reaches a certain level, the friction between the bones increases, and people feel pain when walking, which is often referred to as degenerative osteoarthritis. We ordinary people usually exercise, in addition to weight loss and bodybuilding, etc., mainly to improve the level of function of various tissues and organs of the body. Generally speaking, in the growth period of adolescents, the purpose of exercise is to improve body function and promote growth and development, and after about 25 years old, growth and development has stopped, after this exercise is to maintain the function and slow down its rate of decline, for the middle-aged and elderly people after 50 years old, exercise can only slow down its rate of decline. This is an irresistible law of nature that the human body functions with age, and can not be violated, there is no “immortality”. With the development and progress of society, people’s health level is gradually improved, the life expectancy of people is also growing, modern people pay more and more attention to their own image and health, so exercise is becoming more and more popular, and gradually become a way of life. Proper physical exercise is good for maintaining health, but if you exercise too much, not only can not improve the body’s function, but also lead to a decline in function, bringing burden and injury to the body. Therefore, in order to have a healthy body, it is necessary to consult medical experts in the relevant disciplines, if necessary, according to their own situation, scientific and reasonable exercise. Remember: life is exercise, excessive exercise is damage.