I have this book but have not read it yet - my problem is that I often physically cannot breathe through my nose either due to mild allergies or damage from sinus infections or maybe a mildly deviated septum.
Daytime though I try to breathe through my nose when possible and also breathe as deeply as possible - it really is a waste that most people only use a small part of their lungs
I had a similar problem with chronic stuffy nose, recurring sinus infections, and a deviated septum. But Buteyko breathing practice was a big part in me getting better. There were other things I did too, but paradoxically, breathing through the nose (and the uncomfortable "suffocating" feeling that happens when you do this while having a stuffy nose) causes the CO2 in the body to rise, and if you keep this up for a little while, it causes your nasal passageways to expand and the mucus to thin and drain, which actually allows you to keep breathing out of the nose. Breathing out of the mouth on the other hand, has the opposite effect, which perpetuates the vicious cycle.
So, you just have to stick with it and study the exercises and tape your mouth shut if necessary at night. Things will get better, it just takes practice.
If I were to tape my mouth closed at night, I'm confident I would die. Other comments are mentioning liability and not running your own CPAP, but this is exactly the kind of advice that should be put before a doctor before doing.
People with severe apnea die from it all the time. You'll wake up if you need to breathe...until you die of a heart attack or stroke from all the damage.
Suffocation is what causes the heart attacks and strokes. It's what killed Carrie Fisher. Granted, she had chronic underlying health problems and was apparently on a bunch of drugs, but the proximate cause was apnea.
I've seen Butekyo breathing mentioned on other sleep apnea forums. Could you recommend an website that teaching this breathing practice? Also, how long did it take for you to start sleeping better once doing these exercises?
Daytime though I try to breathe through my nose when possible and also breathe as deeply as possible - it really is a waste that most people only use a small part of their lungs