We hiked a 4 mile trail today from the top of Pioneer Point down to the river in Black Canyon. The trail started at an elevation of 8040 feet and ended at the bottom at an elevation of 7160 feet. It was about the same as taking the stairs of a 90 story building from the top to the bottom and then back up again. It's a noticeable difference hiking at these elevations. There's just not alot of oxygen up here.