Many mystical traditions talk a lot about breath and breathing. Yoshinkan Aikido is known for its founder's adherence to the idea of kokkyu rokkyu- breath power. Buddhism in its many variants has meditation exercises based around observing your own breathing. And then there are the stories of 'chosen' children being breathed on by enlightened folk, a passing on of knowledge or wisdom it is presumed.
But few really vaulable things can be presented except through a shape shift, a metaphor or analogy or story. So what is the analogy for breath? Expanded sensations of conciousness, where connectedness and wellbeing rather than excstasy are self-observed, bring forth the insight that 'the world breathes', 'conciousness breathes in time with all living things'; you can breathe more 'deeply' by being more 'open' to the experience. Your own breathing has nothing much to do with this cosmic breathing except to provide a way of understanding it.
People become obsessed by breathing exercises partly because oxygen starvation/overload can cause pleasurable or strange mental states. But this is a dead end. Breathe to stay alive and breathe to connect with the idea of a universe of connected consciousness.