Sleep-deprived with frostbite, Aaron won the world's toughest footrace

Pushing the human body to its limit, he vowed to at least finish what he started. He ended up doing much better.

Exclusive: With just 48 hours remaining in the world's toughest, windiest, and coldest footrace, Aaron Crook's body was in agony.

The temperature had dropped to -42 degrees, and he was sitting in third place in the grueling 620-kilometre race across the Arctic Circle.

Having slept only 11 hours over the course of seven exhausting days, he had pushed his body to the limit. At risk of hypothermia setting in, he pressed on, overtaking two competitors to claim victory in the race.

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The Adelaide father didn't plan on winning the race, but he was determined to finish it, competing against 15 other ultra-athletes.

He told 9News.com.au that the race was "extremely hard," but he was "pleasantly surprised" by how well his body held up.

"The plan at the beginning... I didn't want to go out too strong, especially considering that the race has a history of lots of people finishing up within the first 24 hours," Crook said.

"I gave myself a chance to get into the first checkpoint, which was about 65 kilometres. When I got there, I was feeling pretty good.

"I decided to push on and I wouldn't sleep, and that was the beginning of what made my race a very consistent one."

Skipping sleep at the first checkpoint set the pace for Crook's race, and in total he only slept about 11 hours over the seven days.

Pushing on, Crook progressed in the race at a good rate, not overly fast.

"I got to the checkpoints and made sure in and out of them. I was a lot faster at the checkpoints than all of the other competitors in the race, which meant that I slept a lot less than everyone else," he said.

"In the end that meant I was right towards the front of the race. That gave me an opportunity to win it... that seemed to pay off in the end."

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'Body under attack'

The Adelaide father admitted there were only a handful of times when he truly struggled, and 48 hours before finishing the race was one of those moments.

While he expressed the weather was relatively mild, the final days were tough.

"It was sitting about the -25 degrees range, but it wasn't too windy. It was manageable in terms of layering and making sure I wasn't sweating but was warm enough," Crook said.

"The last couple of days, the wind really picked up and it got closer to the -40 degrees with the wind chill and a bit over -42 degrees.

"It felt like the body was under attack in those conditions."

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Crook found himself facing the very real prospect of developing hypothermia, as the wind continued to pick up.

"Those last two nights were probably the only time during the race where I actually felt like my life was probably a little bit of risk," he said.

"The wind was hammering my face and I could feel damage occurring on my nose and on my eye. Those conditions, you really can't stop, because if you stop, then, it's almost like you're putting your life at risk because hypothermia is a real issue really quickly.

"You have to keep moving. Keep that in mind, you've been moving for five days with no sleep. The body is in a lot of pain.

"You're constantly accruing more damage on your hands and on your face from the cold temperatures."

Despite the grueling conditions, Crook said there was never a point where he felt like he couldn't keep pushing ahead.

He credits mentally repeating several mantras during the race to his success.

"I kept reminding myself that I was able to be there in the first place, throughout the entire race, I felt incredibly lucky to be able to do it.

"I reminded myself of that. I would just constantly say to myself, 'I can feel my fingers and I can feel my toes, I'm warm enough in my core, therefore, I'm okay and can keep moving'."

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Final push to the finish 

With just a day left in the race, Crook made an incredible comeback, moving from third place to claim the win.

He had left the final checkpoint about two hours behind the two competitors ahead of him.

When the pair stopped for some sleep, Crook made the most of the opportunity, charging forward and crossing the finish line with little to no rest.

"I actually was able to get past them while they were sleeping and then I just went really hard to the finish line," he said.

"The finish was quite exciting as exciting as a finish to a 620 kilometre race can be."

Crook believes his move from the beginning to sleep as little as possible was a main factor behind his success.

"I thought that I would be moving for 18 hours and then I would get like four to six hours of sleep every day," he said.

"In reality, there was a lot more movement and there was a lot less sleep, so I probably slept a total of 11 hours over the seven days and 22 hours it took me to finish the race.

"Going into the race, I didn't think it was possible for a human being to do. It was incredible that I was able to move for that duration of time without sleep, but it was crucial to winning the race."

Crossing the line was a "huge relief", according to Crook.

"I'd been dreaming of finishing this race for five years, I was picturing touching that sign at the (end). When that did happen and knowing that I'd actually won the race, I was filled with relief and gratitude," he said.

"I was just really proud of myself for exceeding my expectations and knowing that so many people back in Australia were following my progress."

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'Proud' of fundraising total 

The father was the only Australian among 15 athletes who completed and was raising money for The Sebastian Foundation and the Adelaide Crows Foundation, which supports youth mental health.

Crook last month said he had admired the foundation's Open Parachute program, which helps equip children with the skills they need to overcome mental health challenges.

Every $15 raised for the foundation will provide a primary or secondary student access to the program for an entire school year.

He has since raised $26,000 for the foundation.

"That's been such a huge part of this. I'm really proud of it," he said.

"We were able to continue to fundraise until after the race, and we've fundraised over $26,000 which exceeded our goal. It is a really significant amount of money and is going to make a huge difference in so many children's lives.

"I'm really happy with the result of the race. I'm blown away by family and friends and small businesses that have come together to contribute to that fundraiser."

Back home in Adelaide, Crook is happy to be reunited with his family and friends, who supported him every step of the way.

He plans to spend the next few months resting after suffering some superficial frostbite on his nose and cheek.

He still doesn't have feeling in the tips of his fingers.

"The body's just got to recover now. It's just a huge trauma, but I'm home now, so I'll have plenty of time to recover," he said.

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