Good stuff.  But when I get to the point where I'm into a vigorous work out, not sure I'm breathing "freely"....feels and probably sounds more like sucking air...

FWIW.......

My experience is the air breathing style I gleaned from some climbers I had become acquainted with while working at Mt Rainier has served me best when it is a situation where one must work hard for a sustained span of time.

I have proven it over and over to myself that it does indeed work. When I find myself struggling on a steep incline or fighting a nasty headwind on my bike or ascending a 3 mile switchback trail (plenty such slogs out west) if I discipline myself to breathe in through my nose and blow hard out my mouth. I calm down and typically can sustain a much longer and steadier pace than if I am huffin and puffin just through my mouth. Scientifically not sure what the dif is but all I know is it works........common practice amongst climbers even in the thin air.

It might not be for everybody, I just know it works and works well for me.

Good one Joe about the "extra protein"  ........ >>Which reminds me of hiking in Glacier National Park, I was alongside Elizabeth lake and a party of 3 were hiking on the other side early in the morning when all of a sudden one of their members started coughing and gagging like he was about to die....It went on for a few minutes...I still remember being very concerned. When we met up I asked if he was OK and all that had happened was that he had gotten a bug caught in his throat! 

As I recall,from my yoga and martial arts days of long ago,breathing in through the nose while expanding the diaphram and then exhaling twice through the mouth was suposed to get rid of all the carbon dioxide and allow more oxigen to be absorbed. It worked well when I could still run. It works well now when paddling hard for an extended period.