WHEN mountaineer George Mallory was asked why he wanted to climb Mount Everest, he answered: ''Because it is there.'' Tristan Miller might know how he felt.

For the Melbourne IT specialist and amateur runner, Everest is a grand (some might say mad) plan to travel the world doing a marathon each week. Why? To see if he can.

He first conceived his personal Everest while basking in a post-ultra-marathon glow, while reading a complimentary copy of Distance Runner magazine. ''In the middle was a massive calendar of marathons all over the world,'' Miller says. ''All these things I'd love to do, all these places I'd love to see. And I thought, 'How good would it be?' ''

That was in April. Since then, 32-year-old Miller has pounded his way through a 90-kilometre torture test in South Africa, taking just over nine hours, and become a victim of the financial crisis when Google closed its Melbourne office and he lost his job.

Both events conspired to nurture the dream. As of now, he has an itinerary, his best mate Darren Foss as a support crew of one, and the best part of the estimated $150,000 he needs to complete his goal, having sold his flat.

''We're leaving on December 20,'' he says. ''Zurich on New Year's Eve is the first one, it starts at midnight after the fireworks. It's going to be pretty cold.''

Having knocked over Zurich, he hopes to do a spot of skiing in the Swiss Alps before flying to Israel. Then it's over to Mumbai, then off to the Canary Islands, Morocco, Italy and Egypt. After that, things get really tough.

As far as Miller knows, there are two other people to have done 50 marathons in a year, but both of them did it within the one country. He plans to raise some sponsor dollars for UNICEF or the World Wildlife Foundation and to sightsee on the way.

''Both Darren and I love to have a good time and we're going to go to some festivals … It's going to be the most amazing adventure ever.''

Perhaps reassuringly, he admits he has no idea if his body can take the punishment of 52 races, another 45 kilometres a week of training and endless flying.

Sports scientist Dr Dan Dwyer agrees that Miller is heading into the unknown, saying he faces challenges ranging from possible stress fractures to chronic dehydration. The real risk will be if he tries too hard to push on, resulting in long-term damage to joints and bones or a chronically suppressed immune system.

''For most people [illness and injury] are self-limiting,'' Dwyer says. ''The danger is that … he might be feeling obliged to run even though he's sick because he feels people are watching him.''

Miller is indeed hoping that people will be watching. He will set up a YouTube channel to document his progress and upload information about his heart rate, times (he's aiming for 3 hours 45 minutes) and kilometres covered. His back-up plan is to have Foss step in to run if he is physically unable, but acknowledges that ''things could get weird'' if he gets sick.

He is also taking a battery of tests, and has sought advice from sports dietitian Alison Walsh, who says one of the biggest obstacles will be maintaining both quality and quantity of food to ensure his body can recover.

''He's got to maintain his weight and muscle mass,'' she says. ''He needs to be aware of his food at all times - one or two days of bad eating could really affect him for the whole week.''

But even given perfect health, great food and no late flights, climbing the mountain will still come down to having the mental strength to ignore the body's perfectly reasonable requests for a break. Which is why Miller thinks he can succeed.

''I love completing things,'' he says. ''I'm the sort of person who doesn't like to give up. I want to be the guy who can say, 'I did that', to have a story that I can tell in 10 or 20 years' time.''