In the early 2000s, Dr. Xavier Woorons, a French physiologist at Paris 13 University, found a flaw in these studies. The scientists critical of the technique had measured it all wrong. They’d been looking at athletes holding their breath with full lungs, and all that extra air in the lungs made it difficult for the athletes to enter into a deep state of hypoventilation. Woorons repeated the tests, but this time subjects practiced the half-full technique, which is how Buteyko trained his patients, and likely how Counsilman trained his swimmers. 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. Other reports showed hypoventilation training provided a boost in red blood cells, allowing athletes to carry more oxygen and produce more energy with each breath. Breathing way less delivered the benefits of high-altitude training at 6,500 feet, but it could be used at sea level, or anywhere. Over the years, this style of breath restriction has been given many names—hypoventilation, hypoxic training, Buteyko technique, and the pointlessly technical “normobaric hypoxia training.” The outcomes were the same: a profound boost in performance.* Not just for elite athletes, but for everyone.
Key takeaway, to slow down your breathing and intentionally take in less oxygen when exercising to grow your endurance. You might feel like shit doing it, but it is supposed to lead to long-term benefits for your endurance and health, while also elevating the positive impact of your exercise. Also, in this book, it mentions that even if we take in slow breaths (i.e every 5-6 seconds), we still get more than enough oxygen for our needs.