There are two reasons for your symptoms: 1. You exercise too hard, and the airflow in the trachea flows too fast, which does great harm to the airway mucosa and increases the secretion of mucus in the airway epithelium, leading to excessive phlegm, viscosity and even difficulty in coughing. 2. When playing games, the wind is relatively strong, and when it is against the wind, a large amount of gas will be injected into the airway, with the same effect as before. The first kind is common in people who do relatively little exercise, especially office workers. The second situation is very common for people who exercise regardless of the weather, especially on windy days. The solution is to keep healthy and do proper warm-up exercises before exercise to avoid the overload of physical function caused by sudden and strenuous exercise. I am a medical student. I hope the answer will help you. Ask me if necessary.