As a kid nerves were crippling. Then it became adrenaline which helped me in the Army before fights. General Patton said he was always short of breath before battle.
I’ve got to be honest, breathing has never helped me pacify anxiety. I’ve tried it since I was a kid in sports, I’ve tried it in meditation, tried it in military, big speeches, etc. I could go jog a mile and still feel that anxiousness. To me, it’s just best I think about the task at hand and try to figure out how to win the moment. Envisioning helps