There are two kinds of muscle exercise, anaerobic exercise and aerobic exercise, that is, oxygen inhalation and non-oxygen inhalation. There is a big difference between them. Aerobic exercise, while breathing, mainly exercises chest expansion. If you want to exercise your muscles, you'd better choose anaerobic exercise. Hold your breath and don't exercise your chest hard. If you only rely on muscles, muscles will grow faster and stronger. I hope my answer can be adopted.