IT'S a big step up from number-crunching to yomping across the Arctic.

Hampshire accountant David Aston is set to prove he is up to the challenge by taking part in a race which will pit him against hazards such as ferocious polar bears, sub zero temperatures and thin ice.

David, 35, of Northbrook Avenue, St Giles Hill, Winchester, will ditch the spreadsheets next April in favour of one of the toughest challenges on Earth, the Polar Race 2005.

The 350-mile, three-week slog involves dragging a sledge across some of the chilliest and wildest terrain on the planet, from Resolute Bay in Canada to the Magnetic North Pole.

"I have never been pushed physically in this way before and the Polar Race will give me the opportunity to test myself to the limit," said David, a partner at accountants Baker Tilly.

"I also wanted to gain a different perspective on the world by seeing what things you take for granted in everyday life. Going to a part of the world that is totally untouched by man also appeals."

Preparing for the Polar Race involves one rather unusual training method.

"I now have to eat as much as I possibly can, which is actually harder than it sounds, particularly when you are full," David said. "Putting on weight is vital because at the moment, if something goes wrong, I would not have enough weight and physical strength to be able to deal with demanding situations."

There's no chance David will be too well covered to attempt the task though.

During the race he will burn 10,000 calories a day and lose about a stone a week.

David will be learning new skills such as navigation, first aid and dealing with polar bears, and in case any get nasty he'll be armed with a high-powered rifle in his kit.

However, he said that one of the toughest parts of the trek will be getting started every morning.

He added: "Most days will be spent getting nearer to checkpoints so I think the repetitive routine of the day will challenge me."

The wild nature of the Arctic will ensure David's repetitive routine is livened up.

"Blizzards may occur to break up the day," David said. "These will be a real challenge in themselves."

David must raise £19,500 in sponsorship for the task, which he is confident of getting.

He will also be raising money for charities the Anthony Nolan Trust and Mencap.

Anyone who would like to sponsor David should contact 01256 486800 or e-mail david.aston@bakertilly.co.uk.