Researchers studying cold weather endurance at Yukon Arctic Ultra vexed by extreme cold weather

CBC

08-02-2025

Extreme temperatures in this year's race causing many research subjects to drop out
A wave of scratches from the Yukon Arctic Ultra this past week might be frustrating for racers and organizers, but it's also turning into a headache for one German researcher.
Mathias Steinach is with the Center for Space Medicine and Extreme Environments in Berlin. His work focuses on the physical effects of extreme cold on high-performance athletes.
Yukon Arctic Ultra racers travel as much as 600 kilometres by foot, bicycle or on skis. This year, temperatures at the race start in Teslin were around -40 C, and they've stayed in the –30s for most of the race.
The event, where 34 of 61 competitors have dropped out thanks largely to frostbite caused by extreme cold, would seem to be the perfect laboratory. But Steinach said 10 of the 14 runners participating in this latest study have dropped out of the race.
"Two by three by one by two, they are dropping out," Steinach said. "Unfortunately, there's nothing we can do about it. And so of course this is negatively impacting our research."
Participants in the study wear fitness monitors that collect reams of physiological data including heart rate, calories burned, number of steps taken and so on.
Athletes started wearing the monitors in Whitehorse even before the race started, to give researchers some baseline data to compare with what's happening to the athletes' bodies during the race.
This year's Ultra course is following the Yukon Quest's new route between Teslin and Faro. Much of the route runs along the Canol Road, which features numerous undulating hills. Ultra organizers suspect the exertion needed to crest those hills is contributing to the high dropout rate.
"This is a huge impact on the physiology on energy transfer, energy expenditure," Steinach said.
"People cannot remotely eat as much as they [exert themselves]. The energy has to come from somewhere. So that's coming from the bodily energy stores. So fat mass, for example. And so I'm interested in how the body adapts to these changes, how huge the impact is."
Race organizer Robert Polhammer said participation in the study also offers something to competitors.
"It's interesting for the athletes because they do get a lot of data and information about themselves if they want to, which would help them with their performances in the future or maybe finding out how they can improve, what they maybe did wrong."
Steinach has been a co-author on numerous papers about athletic performance in extreme cold, including previous iterations of the Yukon Arctic Ultra.
He said even if there isn't enough data from this year's race for a proper peer-reviewed paper, researchers could still publish a case study, similar to one the Centre for Space Medicine and Extreme Environments did on another punishing trek: the first woman to walk across Antarctica unsupported.