In fact, the whole field of breathing and breath-work has enormous potential for improvement, as most prevailing ideas about breathing promoted in yoga, Pilates, and meditative methods tend to focus on taking big, deep breaths — which is actually the opposite of what you should do.
My biggest disappointment is that I didn't integrate the Buteyko Method into my own health practice earlier. When looking back, with regards to high-intensity exercise, I clearly experienced some of the side effects of mouth breathing before I incorporated this method. When I did Peak Fitness, especially the seventh and eighth repetition, I was frequently so hypoxic that I'd almost pass out.
For everything – if you're interested in athletics or, more importantly, if you're improving the longevity and the quality of your life, sleep apnea or anxiety, the Buteyko Breathing Method is a powerful and inexpensive tool. I strongly recommend you consider integrating it into your lifestyle, and when you're ready, into your exercise. Just remember to progress slowly with exercise and gradually decrease the time that you need to rely on mouth breathing."