Melbourne mum uses fridge to prepare for Arctic temperatures in ultramarathon

A Melbourne mum is spending time in the fridge to help her prepare for one of the toughest ultra marathons in the world. 

Sia Kindberg is training at the University of Melbourne's Carlton campus, where academics are helping her to acclimatise to the sub-freezing temperatures she's about to run into.

In 11 weeks, the 42-year-old from Moonee Ponds will fly to the Arctic Circle where she'll join 39 international competitors in Ice Ultra.

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It's a five-day race across 230 kilometres of bitterly cold terrain.

"The darkness and the isolation doesn't scare me. I find it a bit peaceful to be alone and just to have that beautiful nature for yourself is so rare that you get that," Kindberg said.

Melbourne University researchers are hoping Kindberg's training will help her cope with the Arctic conditions - which could reach minus 40 degrees.

"Ultimately we're trying to improve her chances of completing and hopefully winning the race," the university's Patrick Bradfield-Smith said. 

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The race is a delicate balancing act.

"The second she stops moving she feels the cold but if she moves too fast she overheats," University of Melbourne's Jaqi Coelho said.

Historically, just 33 percent of competitors in this marathon make it to the finish line.

Kindberg will be the first woman to represent Australia in the race.

"When things get tough I do say 'why am I doing this? That's it, I'm retiring, I'm hanging up my boots'," she said.

"You come through the finish line and the pain is gone and then you're signing up for another race."