12/22/2013 04:05 EST | Updated 02/21/2014 05:59 EST

British runner nears end of cross-Canada mission

A 27-year-old British man seeking to be the first person to run unaided across Canada was in Alberta Sunday before tackling the next step of his mission — the Rocky Mountains.

- You can track McDonald's location as he heads into the mountains here.

Jamie McDonald is three-quarters of the way through his cross-Canada run after arriving in St. John's, Nfld., on March 9. His goal is to raise money for children's hospitals in each province he runs through, as well as for two children's care centres in the U.K. He's doing it while dressed as the superhero, Flash, and pushing his camping gear in a baby stroller.

"The last month has become really, really tough," McDonald said while in Calgary on Sunday. "I've been battling –40 C, I ended up getting frostbite on my nose. It turned brown for two weeks, I thought I was going to lose it."

As a child, McDonald spent nine years in and out of children's hospitals in the U.K. while receiving treatment for a rare spinal condition known as syringomyelia as well as a weak immune system.

The symptoms included numbness in his legs, epilepsy and immune deficiency but he said after he started moving more at age nine, his symptoms began to decrease.

Since receiving treatment, he has gone on to complete several adventures around the world in the name of raising money for children. 

Trying to give back

In 2012, McDonald cycled from Bangkok to his hometown of Gloucester, U.K., a journey of more than 22,000 kilometres. Just two days after finishing that mission, McDonald decided to challenge the world static cycling record, which stood at 224 hours and 24 minutes.

He shattered it, spending 265 hours — or more than 11 days — on an exercise bike set up within a marquee in Gloucester, and raising tens of thousands of pounds for the Pied Piper appeal, a U.K. sick children's group.

"I'm trying to give back to the hospitals that helped me out as a kid but I'm also raising money in Canada," McDonald said. "I'm trying to make a difference here as well."

McDonald said his goal is to raise £60,000 (about $100,000 Cdn) for the Great Ormond Street Children's Charity and the Pied Piper Appeal in the U.K., and $40,000 for children's hospitals across Canada.

Rockies are his 'biggest fear'

He's about to begin the final phase of his journey, heading through the Rocky Mountains and eventually to Vancouver.

While the end is near, McDonald said he expects this final leg to be the most terrifying yet.

"I'm facing my biggest fear," he said.

"I've heard the snow can go up half a metre, a metre high, and it's going to be me, pushing a baby stroller, dressed as Flash. It's going to be very unsafe, it's going to be dangerous and I've got a feeling my life is at risk."