The phrase “life is in motion” has been said to be more than vulgar, but usually the most vulgar words contain the simplest truths. With the development of the times, it is found that the incidence of cancer is getting higher and higher. Although the composition ratio of cancer spectrum is changing, the overall incidence rate has been showing an increasing trend, and how to prevent cancer has become a serious topic. Both ancient literature and modern research tell us that insisting on exercise can prevent cancer. First of all, breast cancer is one of the malignant tumors with the highest incidence rate among women worldwide and has a typical hormone-dependent nature. Regular and moderate exercise can effectively increase the body’s energy metabolism, improve the ratio of various substances stored in the body, and reduce the fat content, which is precisely closely related to the formation of various hormones. Increasing exercise and reducing fat can effectively prevent the occurrence of many hormone-dependent malignancies, which is even more important for people with high-risk factors. For example, women with breast cancer risk factors such as family history of heredity, high weight, late childbearing or infertility, and not breastfeeding. Secondly, adhering to moderate exercise can effectively improve the function of the body’s immune system and increase the number of immune cells. As we know, the immune system is the most important protection system for our body. A strong immune system can not only defend against external enemies, but also kill tumor cells in the body itself. In this way, even if a small amount of tumor cells appear in the body, they can be quickly recognized and killed by the immune system. Thirdly, the process of moderate exercise will improve muscle cell activity, stimulate the production of heat in the body, increase the body temperature, and kill cells with poor adaptability to the environment and poor regulation ability, including tumor cells or cells with precancerous lesions. Fourth, during exercise, the metabolic rate of the body’s substances increases, requiring a large amount of oxygen to supply the body for application, which promotes the metabolism of superoxide radicals and other substances and plays the role of antioxidant, thus preventing the occurrence of cancer. Moreover, during exercise, a large amount of waste excreted by the body can be excreted with sweat, which reduces the accumulation of toxic substances in the body and the risk of cancer. Fifth, whether it is the exercise itself or the neurohumoral regulation produced during the exercise process, people are always in a happy and positive emotion. Under such happy or positive emotions, the immune system and various neurohumoral regulating systems improve their own body state with negative feedback, which can effectively improve “their own tasks” and keep cancer cells away. Finally, ancient Chinese medical texts also point out that if there is a regular movement, the spirit will be clear, the internal organs will be strong, and the blood and Qi will be clear. Isn’t this the reason why you can live up to 99 years by walking a hundred steps after meals? Of course, insisting on exercise to prevent cancer should be combined with one’s own physical condition and not to do excessive physical exercise for too long or too much, otherwise it will do more harm than good! To keep cancer away from us, besides insisting on exercise, we should also pay attention to developing good work and rest habits, regular diet structure, pay attention to personal hygiene, and the last point is: smile a lot to keep cancer away!