Today, Karnazes is one of the world's leading exponents of the little-known sport of ultra-marathon running. Unlike the numerous 26-mile city marathons that take place around the world, "ultras" are distinguished by both their unusual terrain, typically deserts and mountains, and quite monumental mileage; anything between 50 and 150 miles.
Perhaps the most disconcerting side-effect to befall ultra-distance athletes is the one experienced by Karnazes two years ago, during the race universally acknowledged as the toughest of them all. The Badwater Ultramarathon is a single-stage race of 135 miles run across California's Death Valley in July - the height of summer. Daytime temperatures regularly push 130C and, according to Karnazes, "hallucinations are all part of the experience.
"-During the 2004 race, I saw a 49er, an old miner, crossing the road with a gold pan in his hand. He was mumbling, 'Water, water'. I emptied my bottle into his gold pan and heard the water sizzle on the asphalt. There was no one there."The heat is other-worldly. You have to run on the white lines because the asphalt is too hot and the sun is so intense I wear a UV-proof suit. I've known it be 104C at 2am." In the 2004 race Karnazes consumed nine gallons of liquid and 30,000 calories of food. Despite a herculean appetite, his body-weight dropped by five pounds before he passed the post in first place in 27hr 22min.
For all his competitive success, it is outside the crucible of competition that Karnazes is redefining the limits of physical endurance, even by his own superhuman standards. In 1995, he ran non-stop from California's Napa Valley to Santa Cruz. There was, for the record, a race taking place, a 12-person team event known simply as "the relay". Karnazes ran the 200-mile race distance solo.
In 2003, he covered 226 miles, again in northern California, again non-stop. A year later, he increased that to 262 miles, or 10 consecutive marathons. And then, last year, the big one, a 350-mile, non-stop loop of San Francisco's Bay area, a feat which took an incredible 80 hours and 44 minutes. "You only stop to change your shoes but otherwise I pee, drink and eat while I run," says Karnazes. "If you're running for three days straight you can't just eat energy snacks, so I eat pizza. I carry a phone and a credit card. I tell the deliv-ery guy where I'm going to be in 20 minutes and he meets me on the corner."