2, the sports expert's point of view is that the best time to exercise is to "follow the sun", the sunrise and sunset, the same applies to fitness. In this time to fitness is the most appropriate. However, air pollution in the city is getting more and more serious, and many people choose to exercise after evening, so more and more people choose to exercise in the evening. It is important to note that you should not do too strenuous exercise one or two hours before bedtime. If strenuous exercise will reduce the quality of sleep, such as exercise after the mind is more awake, in the night more sleep, too much exercise, the whole body muscle soreness, the spirit of the end of the exercise for a long time in a state of tension.