My understanding (open to improvement) is that one reason the body can breathe at a higher rate - and breathe out more CO2 than is normally ideal - is to compensate for an overly acidic state. I think this is related to what Yerrag is referring to, though I'm not up with the details of how the kidneys etc handle these issues.
When I came across Buteyko's ideas, I made more progress with breathing when I attended to diet too, including more of those alkaline minerals as well as attending to blood sugars and other factors.
When I came across Buteyko's ideas, I made more progress with breathing when I attended to diet too, including more of those alkaline minerals as well as attending to blood sugars and other factors.