ARD, as an avid running ... I was surprised to find myself out of breath on at some of these hikes. Being in good physical condition is only half of the battle, the other half is learning to breath at higher elevations. I live my life at sea-level (on the FL coast) ... 6000-8000 feet up is a real change for me. The other factor is the heat, which really did not bother me as again ... I live in FL. My skin did get very dried out as there in no humidity there.