The key is learning to control your breathing , in between rounds . For instance. Don’t let your self start panting uncontrollably like a dog, make your self hold the breath, then exhale, then breath deep, and hold.. You be in control, not the other way around, when you master this you will be fine,. Its some what of an art form. . You want to learn to exhale when throwing punches no only to maximize you force ,but also to prevent you from having the wind knocked out of you ,when you get return fire, which usually comes at the same time or immediately after you let your punches go. . Nothing worse then breathing in while getting hit in the body. Good luck!