MT- I am going to give your breathing method a try this June on the very steep up hill portage from McAree to Pond/Gratton.

I had a highschool basketball coach back in the 70's tell our team to breath through our noses and take deeper breaths from the diaphragm area for peak efficiency. Of course, we were all mainly mouthbreathers ... we all thought he was nuts... but he must have been ahead of his time.