Exercise in winter consumes a lot of heat energy and is easy to get tired. The time and intensity of exercise is based on the first principle of self-fatigue. If you are too tired, your resistance will drop. Not only can't keep fit, but it will make pathogenic bacteria take advantage of it, which is not worth the candle. Warm-up activities before winter sports must be fully in place, otherwise it is likely that muscle strain and joint sprain will be caused by low temperature, reduced muscle extensibility and stiff joints.