Fitness fanatic Nick Tiller is preparing to run 156 miles over six days -- that's pretty much a marathon a day. Oh, and he will be doing it in 50-degree heat across the Sahara Desert in southern Morocco. Why? To raise money for the Royal Marsden Cancer Campaign.
The 28-year-old physiologist tells People: "I started doing marathons and kept wanting to push myself, and I have always wanted to do something for a cancer charity."
Mr Tiller, who is one of 200 people from the UK competing in the race, will have to be completely self-sufficient for its duration, carrying all food, clothes, a sleeping bag, medical kit and an anti-venom pump to protect against snake bites and scorpions, in a 10kg rucksack on his back.
"Everyone thinks I am nuts, without exception. But I think you have to be a bit crazy to do something like this."
He recently completed three marathons in three days. The feat, known as the Marathon Des Sables, takes place from March 31 to April 11 next year. What is he most worried about? "Midday temperatures can reach 50 degrees centigrade and I am worried about my appetite being suppressed in the heat. Knowing what to take in the backpack is also a worry. There have also been cases of people getting lost in the desert." Mr Tiller is running around 100 miles a week in preparation.
"This is without a doubt the toughest event I have entered, and the decision to do so was not made lightly. I also believe that anyone has the potential to do something like this." Umm.