A man who doctors feared would become wheelchair-bound as a child has ran the equivalent of three marathons a day for an entire week.
Jamie McDonald ran a total of 524.4 miles (843.9km) over the seven days, finishing on May 6, only stopping for a 90 minute break a day to let him sleep.
The 32-year-old managed to eat and drink while running on the treadmill, placed in a marquee tent in his home city of Gloucester.
Mr McDonald was diagnosed aged seven with rare spinal condition syringomyelia, which can cause muscle weakness and even paralysis.
The Pride of Britain award-winner spent his childhood in and out of hospital as baffled medics tried to understand why he was so poorly.
But miraculously, Mr McDonald 'grew out' of his condition, and now, despite all odds, is to become a second-time record-breaking athlete.
Jamie McDonald, 32, who was feared to become wheelchair-bound as a child has ran the equivalent of three marathons a day for an entire week
Mr McDonald ran a total of 524.4 miles (843.9km) over the seven days, only stopping for a 90 minute break a day in which time he would sleep. Pictured at the finish
The 32-year-old managed to eat and drink while running on the treadmill in a marquee tent in his home city of Gloucester. No stranger to charity work, Mr McDonald has already raised more than £760,000 ($1million) for sick children over the last five years, becoming well known for his alter-ego 'Adventureman'
Mr McDonald, pictured as youngster with his mother, Anne McDonald, spent his childhood in and out of hospital as baffled medics tried to understand why he was so poorly
His achievement has yet to be verified by Guinness World Records, as officials must pour over hours of CCTV to check no rules were broken.
However, the previous world record distance for seven days of constant running on a treadmill was 513.97 miles (827.15km) set by Marcio Villar in Brazil in 2015.
No stranger to charity work, Mr McDonald has already raised more than £760,000 ($1million) for sick children over the last five years, becoming well known for his alter-ego 'Adventureman'.
The week-long run, in aid of his co-founded charity Superhero Foundation, follows a 5,500 mile run across the US. Over 11 months, he raised more than £162,000 ($210,000) in a 210 marathon coast-to-coast.
And in 2014, he was named Pride of Britain's 'Fundraiser of the Year' for the West after a coast-to-coast run across Canada which raised more than £250,000 ($326,293) and spawned a number one best-selling travel book, raising more than £383,200 ($500,000).
Mr McDonald topped the previous record on May 6 at 10.30am, with more than two hours to spare. He ended the feat in chronic pain and sleep deprived.
As he stepped off the treadmill, he told the crowd at Pillar and Lucy Square in Gloucester Quays: 'You do know what they say about world records? Not just beaten but they have got to be smashed.
This morning, after celebrating the end of the week with a large curry, Mr McDonald said he has a high temperature and everything has seized up.
Mr McDonald said he was 'born sick' before a spinal condition diagnosis at the age of around seven years old. Pictured with his mother as a baby
Mr McDonald, a fitness fanatic, began fundraising with sport seven years ago. Pictured recently during a marathon across America
Mr McDonald doesn't remember much of being ill as a child but had dizzy spells, a low immune system and struggled to eat. Pictured with his older brother when he was a child
He added: 'I can’t help but feel like everything is one big murky dream - like it didn’t happen.
'When I got back to my mum’s yesterday, I just broke down into tears.
'My body feels angry with me. I physically can’t walk or move my legs properly - ironic considering that’s exactly what happened to me as a kid - and I had to be carried into the bath like a baby last night.'
From the age of six weeks old, Mr McDonald constantly felt unwell. His mother, Anne McDonald, was told he had epilepsy and an immune deficiency.
She told MailOnline: 'Name the infection and Jamie had it from the immune deficiency - tonsillitis, eye infections, ear infections, urinary infections. He was always on antibiotics.'
At the age of five, Mr McDonald's infections eased. But in its place came headaches, leg pain, a loss of appetite and dizzy spells that would leave him 'as white as snow'.
Mr McDonald said: 'I was in and out of hospital having tests but my mum really pushed for tests after I would lose feelings in my legs.
'I woke up in the middle of the night and it felt like there were bricks on my legs and I couldn't move them. It happened more than once. That was a really scary time.'
Doctors at Royal Gloucester Hospital arranged for Mr McDonald to have an MRI around the age of seven.
They called Mrs McDonald the same day with worrying results – he had syringomyelia, a disorder in which a fluid-filled cyst, called a syrinx, forms within the spinal cord.
The condition was almost practically unheard of at the time. Now, it is believed to affect less than one in 10,000 people in the US. Its prevalence in the UK is unclear.
Mr McDonald, pictured as a baby with his father, Donald McDonald, and step-brother Lee Little, as in and out of Royal Gloucester Hospital and Great Ormand Street having tests from a young age
Before his diagnosis, Mr McDonald, pictured with his family (being carried by his mother) said he would feel like bricks were resting on his legs and he
