“start extending your exhales”: This kind of long inhale and exhale isn’t possible for very high intensity exercise. Running 400 meters, for instance, would require much more oxygen to keep up with metabolic needs. (Endurance athletes can breathe 200 liters of breath per minute during moments of extreme stress—that’s up to 20 times what’s considered a normal resting volume.) But for steady, medium-level exercise like this, long breaths are far more efficient.
