I recently read a book called The Hindu Yogi Science of breath by Yogi Ramacharaka which was the book highly endorsed by Maynard and other members of his trumpet section. One chapter covers how incorrect and harmful mouth breathing is for the body, Shallow breathing is also harmful. To summarize, the full recommended breath is taken in through the nostrils and utilizes the full capacity of the lungs starting with lower diaphragm and up to mid and upper chest. My problem doing this however is many times I have only a second to breath and then play and I cant get the air through my nostrils fast enough to be of any use. Any one else trying this type of nose breathing while playing and if so how are you getting the full breath in when you a have short amount of time to breath?