I was boondocking along the road to Weston Pass, near Fairplay, Colorado, when I realized, whooo... boy... the air is kinda thin up here. Over 10,000 feet high.
People who are totally acclimated have no problem hiking, running, cycling, skiing... But I was winded after strolling around taking pictures.
Filling my lungs as deeply as possible feels great. It's a special bonus that the air is incredibly fresh. Cool, dry, fragrant—just the way I like it. I can forgive it for being a little short on oxygen.