@sheebacat, without knowing your medical history and not being a doctor myself, just through my own research, I think the respiratory physiologist’s analysis definitely has merit. It’s possible that many of us are breathing incorrectly, and the primary lesson of the Buteyko breathing is to change from the habit of chest and mouth breathing, to belly and nose breathing. It takes practice, but there are YouTube videos that show how to practice belly breathing which is to lie down, place a hand over your chest and the other over your belly and every time you I inhale, your belly hand should rise while the chest hand remains still. The other way to train your body to breathe less is simply to resist the urge to take deep breaths as much as possible and if you do have do, do so through your nose. Have you had your oxygen levels tested?