
"It is important to note that in spite of how it feels when you inhale, you do not actually pull air into the body. On the contrary, air is pushed into the body by the atmospheric pressure (14.7 pounds per square inch, or 1.03kg/cm 2 ) that always surrounds you. This means that the actual force that gets air into the lungs is outside of the body. The energy expended in breathing produces a shape change that lowers the pressure in the chest cavity and permits the air to be pushed into the body by the weight of the planet's atmosphere. In other words, you create the space, and the universe fills it." -- from Yoga Anatomy by Kaminoff & Matthews (pg 6)