The body has two opposing nervous systems that act to either speed up or slow down various functions of the body.
How you breathe determines which nervous system is activated.
Startled by a bear, you would likely take an open mouthed, gasping breath. When under stress, we cry, scream, gasp, and run to save our life. This gasping rush of air through the mouth fills the upper lobes of the lungs where there is a predominance of fight-or-flight emergency stress receptors that activate the sympathetic nervous system.
Think of a baby nursing. Their mouths are closed and they gently breathe through their nose. Nose breathing drives inspired air through the turbinates in the nose that drive the air deeper and more slowly into the lower lobes of the lungs, where there is a predominance of calming and restorative parasympathetic receptors.
Nose breathing calms us down, and mouth breathing stimulates us. This ancient wisdom was found to be true in a study we published on nose versus mouth breathing in The International Journal of Neuroscience.
In our study, nose breathing during exercise was found to boost brain wave coherence, meditative brain alpha waves, slower breath and heart rates, lower blood pressure, decreased sympathetic tone, increased parasympathetic tone, better endurance, and significantly less discomfort during exercise.
Transcending the neurological benefits of breathing mentioned above, pranayama techniques were geared more toward moving the body’s subtle energy.