They did well. But they don't want to say how well just yet, lest they burst their own bubble before the TV episode of Boundless airs in April featuring the Yukon Arctic Ultra race.

Simon Donato and Paul Trebilcock chose the Yukon Arctic Ultra as one of the extreme races for season two of the docu-series, describing it as one of the toughest races on the planet.

In their first season last year, they produced 10 episodes from endurance races around the world.

During the 250-kilometre run across the Sahara Desert, for instance, they experienced scorching temperatures of 45 C. Donato and Trebilcock chose to come north for a segment in the second season to experience the landscape and the challenges of prolonged exposure to frigid temperatures.

They weren't disappointed.

Last Thursday it was hovering around -15 C when they left the start line for their 100-mile race along the Yukon Quest trail between the Takhini Hots Springs and Braeburn.

In all three categories of the Arctic Ultra – marathon, 100 mile and 300 mile – Donato was the only one on cross-country skis and Trebilcock was one of three athletes competing on mountain bikes.

All the others were on foot.

Stefano Gregoretti of Italy placed first in the marathon category with a time of three hours and 35 minutes.

Johnny Anderson of Denmark was the first to reach Pelly Crossing and complete the 300-mile race, with a time of five days, three hours and 40 minutes.

Results from the 100-mile category?

Each participant was required to bring along mandatory gear to ensure they were prepared for the elements, including sleeping bags rated to -35 and cook stoves and pots to prepare meals and melt snow.

Donato and Trebilcock were each accompanied by a film crew of two travelling on snowmachines.

"It was cold but it was not crazy cold,” Trebilcock said in an interview this week of the -25 it dropped down through the night as they made their way to Braeburn.

Trebilcock was carrying about 50 pounds of gear on his bike.

The trail was good, though because the start had to be moved from Whitehorse to the Hot Springs, the race started with a 20-kilometre out and back loop to make up the lost distance.

The out-and-back section got pretty chewed up and there was one stretch for about two kilometres that Trebilcock had to walk his bike, even with his four-inch studded tires.

Other than that section, he said, trail conditions were great. The overflow of water on the lakes, creeks and rivers that had been present just days before during the unseasonable warm snap had turned to solid ice.

Trebilcock said the trick in subzero conditions is managing your sweat.

When he started out, he was wearing a running shirt and a light wind breaker.

Sweating too much means the dampness will eventually turn to cold.

"It's a fine line,” he said of choosing the right clothing. "You gotta get it right.”

The 48-year-carpenter pushed straight through to Braeburn, except for a one-hour meal break about halfway at the Dog Grave Lake checkpoint.

Both Trebilcock and Donato described the scenery during the day as breathtaking.

But through the night, Donato's eyes and headlamp were fixed on the trail.

More than once, he was forced to ditch to slow down his speed.

When you're going downhill on skis in pitch black with a toboggan full of gear in tow, its difficult to determine just how much further to the bottom of the hill, or just how much more speed you can expect to pick up, he said.

Sometimes, Donato added, its best to ditch and slow yourself down as opposed to crashing at high speed further along.

"Fourteen hours of darkness, that was the longest night I have ever had,” Donato chuckled. "If you are doing well and you are moving well, it does not seem like a particularly difficult race. But if you get out there and you have to start fixing skis, and you get dehydrated, you are a long way from help.”

Donato said there were times he didn't see his film crew for lengthy stretches as the crew would travel ahead to prepare for a shot.

"I am pleased with how it went,” he said.

The resident of Canmore, Alta. set a Yukon Arctic Ultra record by becoming the first participant to complete the 100-mile section on skis in his first attempt.

Donato and Trebilcock both commented on the hospitality they received while here from both race organizers and the general public.

There were a few times people came up and complimented them on their TV series, he said.