The perfect breath is this: Breathe in for about 5.5 seconds, then exhale for 5.5 seconds. That’s 5.5 breaths a minute for a total of about 5.5 liters of air. You can practice this perfect breathing for a few minutes, or a few hours. There is no such thing as having too much peak efficiency in your body.

Breathing less offered huge benefits. If athletes kept at it for several weeks, their muscles adapted to tolerate more lactate accumulation, which allowed their bodies to pull more energy during states of heavy anaerobic stress, and, as a result, train harder and longer. All of them claimed to have gained a boost in performance and blunted the symptoms of respiratory problems, simply by decreasing the volume of air in their lungs and increasing the carbon dioxide in their bodies.