Our breathing is structurally shallow, since we don’t use both upper and lower lobes of the chest, in other words, it is partial, not total. Normally, we breathe from the lower lobe of our chest . It is easier to do so as the rib cage being broader simultaneously from both upper and lower lobes, we do not starve the body of needed oxygen. This, in fact, is the technique suggested by Patanjali in his fourth step of Astanga Yoga.
We must note that deep breathing is not an exercise (except in the beginning stage) through which quantum of breahte taken in, is maintained at approximately one’s normal level of breathing and no special efforts need to be made to make breathing deep.
The deep breathing injects a rhythmic movement in the way we breathe by regulating breath cycles. Rhythm pervades the entire Universe physically, emotionally and spiritually. Nature, sea, seasons, air, infants etc. everything is survived on rhythm. Whenever and wherever rhythm is disturbed, there is discord. When rhythm in breathing is disturbed, there is imbalance in the body-brain system since the brain and the body are intrinsically in a state of balance and harmony-homestasis.
The speed with which we breathe is gradually becoming faster over the years due to excitement, anxiety and aggression fostered by a competitive and ruthless way of living. This is not the case with infants and children, although infants breathe faster due to imperative of growth. Nevertheless their breathing is rhythmic. Most of us breathe about 15 or more times a minute. In one day of 24 hours (1440 times) we breathe about 21600 times. If we can slow down our speed of breating as suggested by Patanjali and breathe 12 times a minute, taking 5 seconds per every complete cycle of inhalation and exhalation, we would then breathe approximately 4500 times a day less by saving an enormous amount of energy every day of the remaining life. The total energy without wasting any more in this way is saved and conserved. It would not be mind boggling and it would be interesting if scientists are interested in testing the Patanjali’s propositions that have already been proved by expounded yogis having been buried alive under the ground for more than hours without breathing.