Vancouver extreme athlete Pushpa Chandra is on top of the world after winning the women's category of the North Pole Marathon.

Running in -40 degrees, the 51-year-old homeopathic doctor was the oldest woman competing in the race, which had 38 competitors from 14 countries.

"It was the coldest run I've ever done," said Chandra. "To me I'm in disbelief because when you're there you don't know who's a guy and who's a girl because of the way they're bundled up."

She ran the 42-kilometre race, which took place on April 7, in 7 hours and 27 minutes, which included breaks "in order to defrost."

Operated at a drifting Russian ice base at the Geographic North Pole, the event is quite literally run on water: the frozen Arctic sea ice. Contestants must negotiate energy sapping soft snow and small ice pressure ridges to complete the race.

Chandra said that when one of the stewards told her that she was the second woman and that the leader, British runner Daniela Spiridigliozzi, was only a few minutes ahead, her "competitive juices started kicking in."

She won by just over three minutes.

While it was too cold for polar bears, Chandra said the greatest dangers came from thin ice, crack, and severe frostbite.

She said she was amazed "to be running on water" and to be standing on top of the earth, where there was no east or west.

She said she had no plans for her next race.

"My plans seem to always evolve on their own. This time I had a great sponsor. I'd love to stay home and garden," she said, laughing.