Patrick McKeown is the breathing coach people find after Nestor makes them care. Irish. Trained in the Buteyko method. Author of The Oxygen Advantage. Athletes like him because he talks about CO2 tolerance and nasal breathing during easy work, not about mysticism. The BOLT score (how many seconds you can hold after a normal exhale before you want air) is his crude fitness test for the respiratory system. Low number, you are probably a mouth-breathing mess when you train.
The daily work is unglamorous. Tape at night if the nose allows it. Keep the mouth shut on easy runs and walks. Slow the breath down. Light air hunger, on purpose, to reset the panic threshold. For people who over-breathe when anxious, that is often the whole trick. You are blowing off too much CO2, feeling air hunger, then breathing even faster.
Hof’s breathing is a big, swinging protocol: heavy ventilation, then a hold. McKeown is almost the opposite temperament. Smaller breaths, nose, biochemical calm. They can live on the same site. They are not the same drill. Do not mix them in a pool.
Buteyko has a true-believer wing. McKeown is more sports-science than that, and still selling courses. Use the free tests. If your BOLT is 10 seconds and you snore, the nose and the night are the project. If you have serious asthma, this sits next to medical care. It does not replace it.