SHE has run in searing South African heat and through the sub-zero temperatures of the Antarctic.

But now adventurer Shona Douglas Thomson is to take on her toughest challenge yet - racing along the frozen Tuul gol river in Mongolia.

She and two others, expedition leader David Scott and runner Dr Andrew Murray, will vie to complete the inaugural Genghis Khan Ice Marathon in January next year.

Their efforts will help raise money and awareness of charities Riding for the Disabled (RDA) and the Scottish Association of Mental Health (SAMH).

Shona said: "It was the hottest day of the year last year when I got a text message from David and Andrew to say, 'we have a little proposal for you'.

"The 'little proposal' turned out to be running a marathon on a frozen river in Mongolia.

"I had a lot to think about before saying yes. But so few people get to go there and it was just too good an opportunity to turn down, particularly with the great team we have got together."

Mongolia is often considered one of the most savage places on earth, due to its plunging temperatures of minus 40 and its sparsely populated land.

This means the inaugural Genghis Khan Ice Marathon will be one of the toughest runs the competitors will ever undertake.

Husky dogs will patrol the route of the race to ensure roaming packs of wolves do not endanger the runners - and they will also pull supplies for those taking part.

Shona added: "In terms of running preparation, I will just train as I would for any normal marathon.

"When I trained for both the polar marathons I didn’t do anything particularly different like running in a freezer.

"Just as important, if not more important than the training, is getting the correct kit. I'm being sponsored by Ellis Brigham Mountain Sports for the many layers I'll need to wear to keep warm.

"There is a real risk of frostbite and hypothermia if you wear inappropriate clothing or pace yourself incorrectly on the run."

Andrew, 35, who works as a Sports and Exercise Doctor with Edinburgh University, added: "I can’t say that my support crew has ever been a pack of huskies before, but I’ll be giving it everything I have to get to the finish and avoid frostbite and hypothermia.

"Conditions are expected to be minus 35 to minus 40, but it is likely to feel a little colder with the wind chill. But all those hours training up in the Scottish hills in winter whilst everyone else is enjoying their Christmas festivities will be worth it.

"Everyone will look to do well, but the principle objective is to finish, and have a full complement of fingers and toes to go home with.

"Outer Mongolia is beyond spectacular. Where else could you run down an ice river in an area so steeped in history, with the prospect of a Burns supper, complete with a pipe band to look forward to when we arrive in Ulan Bator?”

As well as taking part in the epic ice race, Shona and her team will help people in Mongolia with the building of homes - called gers - for local people and the donating of medical equipment to rural communities in Outer Mongolia.

They will be staying with local families in basic accommodation - and Shona says she is already looking forward to the hot shower she'll have when she arrives home.

The investment banker said she can remember three showers in her life that has been standout moments - one after running the North Pole marathon, following the South Pole marathon and after climbing Mount Kilimanjaro.

But just as important as the running is Shona's determination to raise money for her chosen charities.

She added: "I have been involved with Riding for the Disabled for a number of years. The work they do is life changing, the way they can offer satisfaction and enjoyment to people.

"It would be amazing if this endeavour helps raise the profile and recognition of what they do.

"And to help raise their profile I'm going to be riding a Mongolian pony when I'm out there - I just hope it's been schooled."

The Evening Times first told of Shona's impressive running goals last year when she vied to become a member of the highly exclusive Seven Continents Club - running a marathon on all seven continents.

Shona, who grew up in Craigmaddie, near Glasgow, caught the running bug in 2010 and has now earned a long series of impressive achievements.

Shona has no plans to rest after her epic trip to Mongolia - she has the Tokyo Marathon to complete in February and part of her preparation for Mongolia is running the Chicago Marathon on October 11.

Scott, 42, who is Mongolian Honorary Consul for Scotland, said: “Effort alone will not be enough. Competitors will need to prepare themselves thoroughly for the frigid conditions, have the necessary quality clothing, and need a fair slice of luck, particularly with the weather.

"We have several teams of huskies to resupply runners, and ensure interactions with the local wildlife are safe.

"And although there is a chance of failure, this is an area of extreme beauty, of vast skies, unique culture, and a rich history. It is also an opportunity for a world first."

The Genghis Khan Ice Ultra will take place on January 26.

To donate to RDA or SAMH see uk.virginmoneygiving.com/team/GhengisKhanIceMarathon or to sponsor Shona email ST@SlowTwitch.co.uk or David Scott david@sand-baggers.com