"You should get some nipple guards," the man said, his legs churning alongside mine.

"Nipple guards?"

"Yeah, nipguards. They're little band-aids to stop any chafing or bleeding. I'll send you a Web link."

"I don't know if you know this," he added, "but when you cross the finish line they take a picture of you. You don't want to look like you took two shots from a sniper in the chest. Trust me, it's not a good look."

Maybe I should explain.

When the rain pelts my window at 6:30 a.m. on a September morning, 100 or more reasons play out in my head why I should not get up and run. One -- and only one -- comes down on the side of rising, stretching and slipping on my sneakers.

George.

George is already out there, parked alongside the muddied canal. Whether I show or not, he will slog through those sopping puddles along the towpath. Since he left his wife, two daughters and the family cat sound asleep in Northern Virginia to run on Saturday, I figure my couch and CD player can probably deal with the separation anxiety.

George is training for his 10th marathon, the 30th annual Marine Corps Marathon, next week. He is one of 30,000. I plan to run the New York City Marathon on Nov. 6. It will be my first and last. I will be one of more than 35,000. Last year, it was the largest race in the world. Everyone who has run either race describes an experience as humbling as it is life-affirming -- and that's before you put on the nipguards.

In casual conversation along the run, George informs me he works for the CIA as an analyst at the National Counterterrorism Center, that he reports to Homeland Security Secretary Michael Chertoff and that he cannot tell me his last name. George's office phone number comes up 571 on caller ID, revealing just the area code. When he said one morning, almost cryptically, "I've got something to show you at Mile 5," my imagination was aroused.

Maybe he asked me to run with him for a reason, to put The Truth to my hands, to pass on a document or ZIP disk that would alter civilization -- or at least allow me to go on a long book leave and come into the office even less.

We stopped after about five miles, just like George said. He crossed a wooden bridge, toward the Clara Barton Parkway. He ducked into a thicket of trees, reached down among the grass and pulled out a small plastic bag. It was filled with Gummy Worms.

"These will keep you going," he said. "You can suck on them and just let them melt in your mouth while you run. It'll keep your energy up."

The next Deep Throat, George was not. But he has kept me going, every Saturday, since I met him and my body began to fray. First, plantar fasciitis, an inflammation in the foot. Then a rolled ankle. Puffy knees and sharp pains in the lower back. They all went away and were replaced by new maladies. Bursitis in the right hip. An Achilles' tendon tighter than the Edge's guitar strings. I ended up on a table covered with white-tissue paper, in a sports medicine doctor's office. The doctor, Craig Faulks, checked me out and I asked about a cortisone shot, finally persuading him to give me one in my right hip.

For the longest time, I wondered why anyone would subject his body to that kind of physical pain and damage. Non-elite distance runners, in my mind, were a) obsessive-compulsive characters with piano-wire thin frames b) recovering addicts from the 1970s and 1980s who now get their high legally through endorphins or c) former competitive runners with many unresolved issues about their athletic prime.

But for the truly physically unable, the question, "Why would you do that to yourself?" is every non-marathoner's rationalization. It makes the sedentary and weekend warriors among us feel better about the fact that, deep down, we have doubts, that maybe we don't have the discipline, commitment and heart to cover 26 miles 385 yards. Training for your first, logging about 500 miles over six months, you don't know if you do.

So I bought nipguards. And bags of frozen peas, which fill in the spaces around joints and muscles better than crushed or cubed ice. I strap the peas around ankles, hips, hamstrings and knees -- so many bags of frozen peas that I resemble a walking frozen-vegetable section. I imbibe something called GU every 45 minutes when I work out. It's a concentrated carbo-load gel sweeter than Fruity Pebbles.

I showed up that September morning because not to would let George, myself and others down: my best friend training 3,000 miles away, who will run New York with me. My podiatrist, James Petko, the Sole Doctor, who papier-mached my flat feet and had orthotics made for my tall build. Ben Cooke, of the Georgetown Running Company, who made sure my gait matched the shoes I bought. Pete Sherry, the 2003 Marine Corps champion and Herndon High School coach, who showed me how to stretch. Terrel Hale, the massage therapist who worked with real athletes in Athens. My good friends, who helped map out drop-off points for Gatorade and GU for that 15-mile July scorcher in Rehoboth.

I always heard how logging 26 miles 385 yards is a great, individual accomplishment. Ask George and the others who got me to this point. They know it's about a community of support, about one leaning on many to keep going.