Altitude Training at The Grand Canyon, Arizona

Monday, August 3

I had never run at high altitude before and the reports I'd read about its effect on the body meant I approached the rim of the magnificent Grand Canyon with some trepidation. This was going to be an epic 14-miler under the Arizona sunshine.

The plan was to adapt to the conditions by keeping a close eye on my heart rate and making sure it hovered around the border of the cardio and peak zone even if that meant slowing the pace right down to cope with the lack of oxygen. We'd spent all of yesterday hiking around the Canyon so we were already getting use to the thinner air without even knowing it.

Research suggests a normal pace of 8 mins/mile becomes 8:45 per mile at an altitude of 5,000 feet above sea level. The there-and-back part of the rim trail I selected started at 7,133 feet above sea level, dipping to 6,800 feet along the way before climbing back to its starting level so I was expecting it to be tough.

But it was also exhilarating. Big Joe joined me for the first half-hour from the Mather Point overlook near the main visitor centre running west until the end of the very steep incline three miles later just after the Bright Angel trailhead. We started running under the Californian Condors at 7am to beat the heat and the cool conditions were perfect. The canyon falling away forever on the right made this one of the most memorable runs available anywhere in the world.

After Joe dropped out I was on my own as the paved path eventually ran out after five miles and the rocky trail tested the grip of my Brooks trainers to the limit. I knew my pace was slower than usual but I was enjoying the run and coping with both the distance and the steep undulations that added up to a 1,104ft elevation gain.

It was just me, a couple of startled rabbits, a mule deer, ravens, turkey vultures and the odd early hiker with one of the Earth's greatest views all to ourselves.

By the time I'd finished 2:16:01 later, equalling the furthest distance I'd ever run, I'd averaged 9:43 per mile, about a minute and a half slower than my usual steady pace. It was the most memorable training run I'd ever done.

After that it was back to Vegas for an overnighter at the MGM Grand and a dip on the rooftop pool before heading down, down, down to Death Valley.