Two: The sun has not yet risen at five o'clock in the morning, green plants have not yet started to produce oxygen, and the air contains a lot of carbon dioxide. At this time, running will adversely affect the runner's respiratory function.
Three: Fitness and running exercises are usually arranged at six or seven in the morning, followed by around 9 am and around 5 pm. Try to choose to run in an environment with good air conditions. The general exercise is arranged in the morning. First, it does not conflict with work. Second, running in the morning has fresh air, which is good for the respiratory system. In addition, after sleep, people's physical strength is restored, but physiologically, people still have a certain degree of inhibition. Morning exercise is beneficial to nerve excitement, mental stimulation, metabolism promotion, and it is of great benefit to maintain abundant spirit and physical strength in a day's work.