In Shin Shin Toistsu Do (The Way of Mind and Body Unification) we say that to breathe properly is to breathe with mind and body unified.
Just as breathing is essential to sustaining life, it is also essential to developing our Ki and life power. Ki breathing exercises, as designed by Tohei Sensei, are a central part of training and represents another opportunity to directly experience and realize for yourself the oneness of mind and body as well as your original connection to the Ki of the Universe. You are already One with the Universe.
Dr. David Shaner