The best time to exercise is from 19:00 to 20:30, because exercising every night during this time has the following four benefits to the body: First, this is not the time when plants are photosynthesizing, so the oxygen concentration content in the air is higher and the carbon dioxide concentration content is lower. Second, the suspended particles in the air are low, so there is no excessive dust mites and dust inhaled into the lungs. Third, the level of human metabolic rate is low at this time, such as exercise during this time will increase the metabolic rate of people, so it will affect the normal resting basal metabolic rate in the body, which will have a multiplier effect on weight loss. Fourth, after an hour of aerobic exercise in 19:00-20:30 exercise body, it will help to sleep, can relieve the stress and fatigue before sleep, promote sleep therapy and improve sleep levels.