I unintentionally pitchfork a clod of manure into my mouth. Sputtering—it tastes like brussels sprouts and farts—I spit it out, finish loading the wheelbarrow with dung, drag it out of the barn, and start running and rolling across the field. This is my 14th round-trip, and I'm being timed; each circuit has to be quicker than the last or they start adding laps. I race past the timekeeper, dump the manure at a compost pile, and head back to the barn.

It's June 26, I'm 17 hours into the Death Race, and, all in all, I'm still feeling pretty strong. A barbwire gash on my head has coated one side of my face with blood, but as I told the medic in my best Monty Python falsetto, "It's a mere flesh wound." My back no longer feels as if the vertebrae are being crushed, but the pain in my knees is definitely worse. It's not raining (at the moment), and my one-person pit crew—stalwart wife, Sue—is running alongside me, pushing peach slices into my slack-jawed mouth. I know I can finish this race. What I don't know is that this is the last time I'll feel good for a month.

I fill the wheelbarrow again and sprint across the hayfield, shit flying. En route, I pass Stefanie Bishop, 27, the fastest woman in the event. She's practically skipping behind her wheelbarrow, turd-flecked blond hair bouncing. At age 51, I'm grimacing, huffing like a horse, while Bishop, halfway into her laps, effortlessly gives me a broad smile and shouts, "Yeah! Go get 'em!" It's twisted. The girl's some kind of superhero.

The next task turns out to be a pond swim. (In the Death Race, you never know what each new challenge will be.) I've been ordered to count out 1,250 pennies and put $5 worth in a plastic bag. After running straight through the night lugging ungodly heavy objects, sitting in the grass counting coins sounds almost pleasant. Except I'm so exhausted that my mind's malfunctioning. I keep miscounting. By the time I get 500 pennies into the bag, the Vermont weather has changed its mind. It's drizzling and I'm shivering.

I stand on the edge of the dimpled pond and watch as the bag of pennies, plus two bags of rocks thrown in as decoys, sink into the chilly water. My job is to go in and retrieve the pennies. Bishop got ahead of me during the counting, and I watch her perform this task with ease—diving in, bobbing back up with the correct bag, and then tearing off for the next mission.

I slide into the water, nuts shriveling, heart momentarily halted by the shocking cold, swim out to where I think the bag sank, and go down. I try feeling my way around in the foot-deep mud but find nothing. I surface for air and then, like a duck, flip ass end up and dive again. I do this five times, holding my breath as long as I can, blindly groping in the billowing muck, and still I don't find the damn pennies. Ten times—no pennies. Fifteen times—no pennies. By now my lips are blue, chest constricted, joints rigid, jaw so stiff I can no longer speak. I'm reaching the point of hypothermia but refuse to give up.

That's always been my problem, of course. I've viewed DNF-ing a race as a fate worse than injury, so I've straggled in with broken bones on more than one occasion. Not reaching the summit of a mountain kills me, so I've almost died trying a dozen times, returning with frostbite or torn tendons or a triple hernia.

Obviously, I don't know when it's time to say uncle. But I have a sick feeling that this race may teach me when it's time to scream it.