THE ONLY man on the planet to run seven marathons in less than seven days on the seven continents is aiming to go one better by smashing the five-day barrier.
Irish ultra runner Richard Donovan starts his epic quest in the extremes of Antarctica running the first 26 mile leg in -20C at the Russian Novo science base next Wednesday.
The 45-year-old father-of-one is doing the endurance challenge on a shoestring budget out of his own pocket to raise awareness of the humanitarian crisis in the Horn of Africa.
His record stands at five days, 10 hours and eight minutes - 130:08.
"It's been very hard to figure a way of knocking off the half day," he said.
"I'm keeping it real - I'm not going in some privileged manner. I'm going against all the rules, no special diet, flying economy by myself, bringing whatever I can fit in one bag. I'll sleep where I can."
Donovan, who was inspired to first attempt the challenge in 2009 after the failed bid by British explorer Sir Ranulph Fiennes, will set the countdown clock ticking from 120 hours.
The first run begins on February 1 when pilots of the Russian cargo plane are given a take-off slot.
Donovan, from Galway and an experienced marathon runner at both poles, said sleep deprivation and massive temperature fluctuations will be the biggest challenge. Despite this he has received no specific medical advice and has not seen a doctor in years.
"I found doing this challenge remarkably hard on the body in a way I did not expect - the temperatures really hit me. I go from -20C to 30C in the space of a few hours," he said.
"The flying itself is hard. I was falling asleep in airports afraid I would miss flights. On the plane I could not sleep but coming into land I was falling asleep and was tired starting the run.
Money raised through online donations at www.worldmarathonchallenge.com will go to Irish aid agency Goal, one of few charities working in the Horn of Africa. Running times will be independently verified at each location.
Donovan has ruled out using energy gels or drinks for fear of sickness and the only supplement he will pack are salt tablets.
"The chances are that my stomach will fall ill so I'm going to eat as simply as I can. Even by the third marathon there will be a lot of fatigue," he said.
"I threw up on four continents the last time - the huge effort and airline food as a staple diet will do that."
Donovan will have about nine hours in each location to disembark, run the course and fly out to the next destination.
"I'm used to moving on dead legs and not having to think about it but that does not deny the fact that they are dead," he said.
"That being said, the experience the last time was a lot more debilitating - it's a unique thing to fly around the world in that time as it is not to mention seven marathons."
Donovan's round the world marathon timeline looks like this:
Feb 1 - 2100 (Sydney time, GMT +11): First leg at the Russian Novo base. Temperature -20C.*
Feb 1 - 2200: Arrive in Cape Town for leg two after six hour 4,200km flight on cargo plane. Average night temperature mid 20C.
Feb 2 - 1630: Arrive in Sao Paulo, Brazil on flight from Johannesburg for third marathon. Average temperature mid 20C plus high humidity. Status 52 miles run and 12,980km flown.
Feb 3 - 0705: Orlando. Marathon number four. Average temperature mid 20C. Status 78 miles run and 19,560km flown.
Feb 4 - 0735: Fly into London Gatwick for fifth leg. Average temperature 5C. Status 104 miles run and 26,560km flown.
Feb 5 - 1345: Arrive in Hong Kong and marathon number six. Average temperature 15-18C. Status 130 miles run and 36,200km flown.
Feb 6 - 1215: Arrive in Sydney with a 1900 deadline to finish marathon seventh leg. Average temperature +25C. Status 156 miles run and 43,540km flown.
*All times local except for Antarctica.