A MARATHON is, for many, the ultimate physical test but for Shona Douglas Thomson, that’s nowhere near challenging enough. Later this month, Thomson, along with a small group of fellow adventurers, will travel to Outer Mongolia to compete in the first-ever Genghis Khan Ice Marathon.

It is impossible to overstate quite how tough a challenge this will be for the group of 10 runners; Mongolia is one of the most sparsely populated places on Earth and the athletes will have to contend with temperatures as low as -40C.

The race will be run not on land but along the frozen Tuul Gol river and just to add some extra spice, the area is heavily populated with wolves. To ensure the runners’ safety, a pack of 60 huskies will accompany them on their 26.2-mile adventure.

It sounds like an almost unimaginable challenge to undertake but Thomson shows no sign of nerves and, in fact, is palpably excited about her upcoming trip. “We’re staying with the nomad community in Outer Mongolia so I think it’s going to be very rural and pretty brutal conditions,” she says. “Mongolia is one of those places on Earth, where you take a step and it’s possible that no-one has ever stood on that piece of land before. I expect it to be absolutely beautiful.”

Thomson is no novice when it comes to running extreme marathons. She has competed in the North Pole, South Pole and Antarctic marathons and, in 2013, became the first Scottish woman to run a marathon on all seven continents. Only 28 women in the world have achieved this remarkable feat. But, Thomson admits, the challenge Outer Mongolia will present her with when the race takes place on January 26 is another level altogether.

“I’ve run in cold conditions before – it was -30 at the North Pole – but -40C is a whole different ball game,” the 38-year-old said. “At the North Pole, I remember being so cold that it goes through to your bones and I also got a bit of frostbite – I still can’t feel my pinkie so I don’t think that’s ever coming back!

“Keeping your extremities covered is very important and we can’t take much water or nutrition with us because it’ll just freeze.” The threat posed by the wolves sounds daunting, to say the least, but Thomson brushes this off.

“That’s not actually all that scary,” she says in a remarkably blasé manner. “It was similar at the North Pole with polar bears, but you just don’t overthink it – although there might be points in the race when I’ll be wishing

I would be eaten by a wolf.” Completing the marathon is just one of the aims of the expedition though, with one of Thomson’s primary goals being to raise money for charity. She supports Riding for the Disabled and the Scottish Association for Mental Health – and the group will also help local projects.

There are few people in the world who have the mental strength to push themselves to the limit in the manner that Thomson will be required to do later this month but she is charmingly modest about why she takes on these exceptional challenges.

“I like testing what your body can do in different conditions,” she said. “Marathons are amazing things to do but nowadays, they’re quite mainstream. That’s not meant in a disparaging way but it’s nice to find a different angle to it.

“With the more adventurous marathons, you don’t know what the conditions are going to be like so you can’t target a time to complete it so in some ways, there’s less pressure and more fun.

“It’s an amazing way to see the world too – Mongolia is one of those places that so few people get the opportunity to go to. It’s so undiscovered and this race is truly a world first.

“Life’s pretty short so I thought, ‘I’ll give it go because what’s the worst that can happen?’. With something like this, you really get to see what you’re capable of.”

The funny thing about Thomson is that despite her achievements, she has never been an elite-level athlete and describes herself as “not a particularly good runner”, which is surely the understatement of the year.

She competed in Scottish Schools cross-country but gave up running when she started university. It was only when she began working that she returned to the sport as a way to wind down from the office.

So, how does someone who began as a recreational runner get to the stage that they are competing in the most challenging races on Earth? “Someone said to me: ‘I bet you couldn’t do a marathon,’” Thomson recalls. “And I thought, I bet I could. That’s how it all started.”

So, with perhaps her toughest expedition to date beckoning, will Outer Mongolia sate Thomson’s appetite for adventure? No chance. “I’m always looking for the next challenge so as soon as I get home from Mongolia, I’ll be thinking about what else I can do,” she said.

“It becomes harder and harder to find unique races, so it’s just about keeping your ear to the ground to find out what’s going on next.”