The purpose of exercise if it is to strengthen the body, generally requires at least 3 times a week, each time more than 30 minutes. Need a certain exercise intensity, heart rate to ensure that more than 100 times / min, such as brisk walking, slow bubble, rope skipping, etc.. If the purpose of exercise is to eliminate excess body fat and reduce weight, exercise needs to be more than 5 times a week. With the increase in exercise frequency effect will increase, because the frequency of exercise and exercise effect has a direct relationship. 1 exercise after the fitness effect on the muscles and the whole body organism system, can keep at least 3 days. That is, the second exercise before the effect of the first exercise has not disappeared, so that the effect of each exercise will be cumulative, to improve physical fitness and increase health. If each exercise interval is too long, destroy the continuity of sports training, it is difficult to achieve the desired fitness effect. And it is easy to produce muscle soreness and fatigue after each exercise, and may even produce muscle and joint injuries.