The Oxygen Advantage: The Simple, Scientifically Proven Breathing Techniques for a Healthier, Slimmer, Faster, and Fitter You

by Patrick McKeown

Abdominal breathing is more efficient simply because of the shape of the lungs. Since they are narrow at the top and wider at the bottom, the amount of blood flow in the lower lobes of the lungs is greater than in the upper lobes.