A Pride of Britain winner will attempt to break the Guinness World Record for the greatest distance covered on a treadmill in one week to raise $1million for charity.
Jamie McDonald, from Gloucester, has already spent the past 11 months taking part in 197 marathons in a coast-to-coast trip across America spanning 5,500 miles.
His trip will end on March 27 in Gloucester, Massachussetts, and just a month later his fundraising efforts will culminate in tackling yet another feat of endurance.
Mr McDonald, who has already raised $1million (£760,000) in the past five years, hopes to smash current record of 513.97miles in a week, held by Marcio Villar.
As a child, the adventurer suffered from a rare spinal condition called syringomyelia, which saw him spending the first nine years of his life in and out of hospital.
Jamie McDonald, from Gloucester, will attempt to break the Guinness World Record for the greatest distance covered on a treadmill in one week to raise $1million for charity
The adventurer has already spent the past 11 months taking part in 197 marathons in a coast-to-coast trip across America spanning 5,500 miles while wearing an Adventureman costume
The condition, paired with a weak immune system and epilepsy, meant his health was so poor that his family feared he might lose his mobility altogether.
But at age nine his symptoms eased, allowing him to slowly become more active. The experience shaped Mr McDonald, and since then he has dedicated his life to raising money to help other sick children.
He said: 'I hope it's with another world record under my belt, but I have to be prepared for the fact that it might not be.
'I will need to run more than 73 miles a day for seven days to even equal the current record.
'The equivalent of three marathons a day for a week is terrifying, but I'll never be in better shape to try. I've run through freezing
