A Breathing exercise I learned from my own trumpet teacher (Claude Gordon Disciple). While you are walking. Breathe through nose one time for each step. Start with two steps. Breath in with each step through nasal passage, Then Hold breath for two steps. Then exhale through mouth for two steps. Practice controlling your breaths so it feels comfortable and natural. When you've mastered it with 2-steps, go on to 3-steps, then 4-steps, 5-steps..10-steps... After a few weeks, you really will notice a different in your breathing and control.