"High Altitude" is a factor. We (BYU) have been fortunate enough to have an extra element to home advantage. Going from sea level to 4,649 feet does make a difference. When I've gone hiking with out-of-state friends, they're always surprised at how much harder it is to breath.
As a side note, I run a lot. My lungs and breathing always wear out before my legs. It is always a little surprising to be on a trip (Oregon coast) or somewhere else and think, "Wow, my legs are tired". But my breathing is ok.
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I've loved reading the comments across your board. You guys seem like a wonderful community. A board of fans that I'd enjoy being part of.