I don't care what others say (in fact, many people don't pretend to understand) I'll tell you my experience. I did push-ups to exercise my strength. I did 40 pull-ups every day when I was in the senior high school entrance examination. It is normal to hold your breath for two years. This belongs to anaerobic exercise. It is unnecessary to inhale when you go down. It is harmless to hold your breath when you go down. On the contrary, it is difficult to go down without holding your breath, but the speed cannot be too fast.