Exercise training is beneficial to the heart. Exercise training will improve the exercise ability and quality of life of patients with cardiovascular diseases, and reduce their mortality and morbidity. Though exercise training benefits in the heart have been well accepted, the underlying mechanism remains to be explored. This review focuses on the main underlying mechanism of exercise benefits in the heart and the research progress of the protective effects of exercise in myocardial infarction, myocardial ischemic reperfusion injury, pathological cardiac hypertrophy, and cardiac aging. It ctims to provide new ideas and strategies for the prevention and treatment of cardiovascular diseases from the unique perspective of “exercise”.