Hi Knitter, I did a course in 2000. Asthma had got very much worse, and initially the buteyko breathing was brilliant - my "control pause" (which is the amount of time you can hold your breath after breathing out) rose from about 8 seconds to 29 at best. This lasted for about 2-3 weeks, then it started decreasing and I could never get it back up again which was very frustrating and disappointing. My buteyko trainer was quite newly trained and had no idea what was happening though she did speak to her own trainer who also had no idea.
A month after I was diagnosed with copd. What i reckoned had happened was that i improved for a while, presumably with my CO2 rising which in Buteyko theory is good as he says that hyperventilation makes us lose CO2 which is not just a waste product but is needed to interact with O2 for optimum breathing and i could breathe much better.
But then as it continued rising as i did more B exercises, i imagine the CO2 got too high - my heart started missing beats which my consultant in my NHS job said does happen when there's too much CO2 in your blood.
So, my concern is that Buteyko can work well for some people with asthma - i think its quite mainstream in Australia for instance - but is potentially dangerous to treat a condition like copd (Im not sure you have this but useful for people living with copd to think about) as we often retain too much CO2 and raising it more can be really dangerous.
I hope this makes sense. The unblocking your nose video above does work from personal experience. jean