Well, based on last night's reading assignment from @
seedsbelize, I tried nose breathing on some of the less anaerobic parts of this morning's flail and was clearly able to raise my pCO2 to the point of frank air panic or the "pink puffer" stage of COPD. There was, however, no accompanying performance benefit of which I was aware. It also occurred to me that I might be genetically unsuited to distance sports and more adapted to chess and philosophical debate, simply by virtue of the conformation of my nose.