Running through Death Valley

MY brain was on fire. My body was burning up. Death Valley had laid me flat, and now it was cooking me. My crew was telling me to get up, that they knew I could go on, but I could barely hear them.

I was too busy puking, then watching the stream of liquid evaporate in the circle of light from my headlamp almost as fast as it splashed down on the steaming pavement. It was an hour before midnight, 105 incinerating, soul-sucking degrees.

This was the point in a race at which I had made a career of locating hidden reservoirs of sheer will that others didn't possess, discovering powers that propelled me to distances and speeds that others couldn't match.

But tonight, roasting on the pavement, all I could summon was the memory of a TV commercial I had seen as a child.

First, there's an egg in someone's fingers and a voice says, "This is your brain". Then the owner of the hand cracks the egg, and, as it sizzles and crackles onto a hot skillet, the voice says, "And this is your brain on drugs".

I saw that image in the scorching night sky. I heard the disembodied voice. But what I thought was: "This is my brain on Badwater."

I had just run 113km through a place where others had died walking, and I had 105 more to go.

I reminded myself that this was the point in the race at which I was supposed to dust anyone foolish enough to have kept up with me in the first half.

I had started this race intending to shatter its record, never mind worry about winning it. And now I didn't think I could finish.

There was only one answer: Get up and run. Whatever the problem in my life, the solution had always been the same: Keep going!

My lungs might be screaming for oxygen, my muscles might be crying in agony, but I had always known the answer lay in my mind.

Tired tendons had begged for rest, my flesh had demanded relief, but I had been able to keep running because of my mind. But not now. What had gone wrong?

Running is what I do. Running is what I love. Running is - to a large extent - who I am. In the sport I have chosen as a vocation, career, obsession, and unerring but merciless teacher, running is how I answer any challenge.

Technically speaking, I am an ultramarathoner. So I compete in any foot race longer than the marathon distance of 42km.

Though I have fashioned a career from running and winning races of at least 80km , most often 161km , and every so often 217km as well as 241km .

Some I have led from start to finish; in others I have stayed comfortably back until the point at which I needed to find another gear. So why was I on the side of the road vomiting, unable to go on?

Never mind my success. People had warned me that this race - this 217km jaunt through Death Valley - was too long and that I hadn't given my body enough time to recover from my last race - a race I had won just two weeks earlier, the rugged and prestigious Western States 100 Mile.

People had said that my diet (I had been eating only plant-based foods for seven years) would never sustain me. No one had voiced what I now suspected might be my real problem - I had underestimated the race.

• This is an extract from Eat and Run by Scott Jurek, published by Bloomsbury.

The Badwater Ultramarathon, run through Death Valley, is known by many as the world's toughest foot race.