Relatively few of the visitors venture below the rim. The National Park Service actively discourages anyone from hiking either rim to the Colorado River and back in one day. The week before our run, a Belgian hiker died of a heart attack ruled to have been caused by heat stress. Temperatures in Grand Canyon increase as elevation decreases. The Park Service wants people hiking to the river to camp at an approved campground along the trail or bunk at Phantom Ranch.
Camping requires reservations, which are difficult to get because demand exceeds supply.
The Park Service recommends that Bright Angel hikers not exceed the 9.2 mile round trip hike to Indian Garden campground. It is 18 miles round trip to the river. After crossing Bright Angel bridge, we enjoy a mile's run along flat terrain that parallels the river before we head uphill. We meet a few hikers who shout encouragement. Around mile 16.5 we hit a tough set of switchbacks.