Tue 10/9 - AM Grand Canyon hike, 4.5 hours incl. 90 minutes of running

Bright Angel trail down, South Kaibab trail back up. Including the stretch of the Rim trail to get from car to trailhead, estimated 17 miles total. 6800' to start, 2400' at the river, 7200' at the end. I had originally planned on a shorter route that cut out the last 2000' or so of descending to/climbing from the river, but being stuck behind the world's most stubborn mule train leader forced me to walk along, staring at a mule's ass, for 3+ miles. This after three other mule trains stopped to let me pass. Stupid cowboy jerk. The senior citizen I ended up walking with was heading to the river and back for the 14th time, in blatant defiance of the first edict laid out here, so I figured I could do something similar. After finally getting around Wilford Brimley and his cheeky band of mule-riding, shit-eating southern tourists at Indian Springs, ran down for the next 40 minutes or so through spectacular scenery of the inner canyon and along the river and over the bridges. Started back up planning on running for 15-20 minutes at a time with 5 minute walkig breaks. This plan lasted until the second walking break ended, I tried to start running again and couldn't move after two minutes. The last 4 miles or so were almost entirely walking, becoming increasingly more strung out and dehydrated all the while. Packed all manner of calories, they barely lasted me. Refilled the camelbak twice, but didn't refill it enough the second time at the river. As a result had a near-Margaret Bradley experience (without the getting lost part, thank goodness) on the way up when the water ran out sooner than I would have liked. Finished as dehydrated as I've ever been. It's difficult to explain how relentlessly hard it was to get up from the river via the S. Kaibab trail. I know people run such things but I have no idea how. The ascent broke me thoroughly, a brisk walk was all I could manage near the end.