On November 22, the Canadian adventurer Len Stanmore began an endurance footrace called The Last Desert—a wild, seven-day, six-stage haul across part of Antarctica. It’s the kind of thing that can devastate even a fit 24-year-old, which is what makes Stanmore’s bid all the more impressive: He’s a 60-year-old retiree.

The story of Stanmore’s transformation into a global explorer is an unlikely one. Before he started climbing mountains, he didn’t even particularly like the outdoors, although he was no stranger to physical exertion. One of his first jobs in his native Toronto was pumping gas for $2 an hour. When Stanmore was in his mid-twenties, he figured he’d never get anywhere if he didn’t go into business for himself, so he borrowed $5,000 from his parents and started his own telecom firm. In the beginning, the firm was just Stanmore and another guy in a truck, digging holes to lay cable. Little by little, though, Stanmore built the business, and, 25 years later, it was the largest telecom contracting company in North America.

In 1998, Stanmore sold his company to a Silicon Valley firm, and the following year, he retired. That’s when he experienced a crisis of faith that launched him on a remarkable run of outdoor achievements. He has climbed the highest peak on each of the seven continents—the Seven Summits—including Mt. Everest. He has cross-country skiied to the North and South Poles. And he has raced through the Gobi, Atcama, and Sahara deserts as part of 4 Deserts, a series of footraces in extreme environments. If Stanmore finishes The Last Desert in Antarctica, he’ll become the first person ever to stand on top of all Seven Summits, ski to both poles, and complete the 4 Deserts Grand Slam. His bid is part of an effort to raise money for Trekking for Kids, a charity that aids orphan children who live at the bases of popular climbing destinations. He hopes to raise $100,000. You can follow Stanmore’s journey in Antarctica at the Trekking for Kids website.

Here, in a conversation that took place before he shipped off for Antarctica, Stanmore discusses his training regimen, the surprising agony of running across salt flats, and how to fight off polar bears.

What exactly is required of you in The Last Desert?
It's a 250-kilometer run, and it’s over seven days. They have one long day, which is anywhere between 80 and 100 kilometers, and the rest of them are 40-kilometer days. It looks like our first day is going to be a 100-kilometer race, so that's going to be a good challenge. Usually they don't have that on the first day, because you're getting used to your gear, and I think for a lot of people, especially people coming from warmer climates, that's going to be very tricky.

You're 60 years old. I assume most of your competitors will be younger.
They're all younger.

So, at your age, how do you prepare for something like this?
Well, I'm pretty strict about training. Normally I'll train between four and six hours a day, six days a week. I'll run between 90 and 120 kilometers a week. Then I'll fill in with another six to eight hours of cardio on top of that, whether it's elliptical or stepmaster or spin bike. Then I'll train another eight hours on top of that during the week with a trainer.

For these races, you have to carry all your gear with you. The pack weighs anywhere from 27 to 30 pounds. That doesn't sound like much, but after about 10 kilometers, you really start to feel it. It's like carrying a two-year-old on your back for the whole race.