In a bright, industrial-looking gym in an old warehouse in Montreal's Saint-Henri district, the bang of clanking metal rises over the sound of Aerosmith blaring out of a small radio, urging weightlifters through their reps. 

Warren Rosenberg puffs his cheeks and powers through a deadlift before lowering the hefty bar to the ground with a thud. The bar weighs 220 kilograms — about 485 pounds.

"I'm feeling a bit jet-lagged," Rosenberg says, resting his hands on his hips below his weight belt.

He's just flown back from a work trip in Singapore, but duty calls. There's not much training time left before the big fundraiser he's organized here at Epicentre gym in support of the Cedars Cancer Foundation.

Besides, as a strongman competitor, Warren Rosenberg is no stranger to heavy burdens. 

"Lifting cars, atlas stones, throwing kegs, lifting logs, all that wonderful stuff you see on ESPN every Christmas," he quips.

But the heaviest burden he had to bear was one he couldn't train for.

Immune system down to zero

Rosenburg had been feeling ill for a few months when, in April 2016, he described him symptoms to his doctor — trouble breathing, cold sweats and a racing heart when he climbed the stairs.

His doctor told him it was probably just the flu.

He shrugged it off, continuing to do "crazy" things at the gym, such as a move called Conan's wheel, where he carried more than 400 kilograms (900 pounds) while walking in a circle.

"I went home, and all the blood vessels in my face had blown," he said. "I looked like a leopard."

One day a co-worker urged him to go to the hospital. He walked into the emergency room at the McGill University Health Centre and didn't leave for 35 days.

It turns out that trouble breathing and those broken blood vessels were caused by a tumour in his nose: a myeloid sarcoma.

He was diagnosed with acute myeloid leukemia. It had a 27 per cent survival rate, according to the experts at Cedars.

On his 44th birthday, Rosenberg started seven straight days of chemotherapy, kicking off six months spent in and out of hospital — most of it long stretches where he couldn't leave his room at all. 

"Your immune system goes down to zero. Absolute zero," he said.

'Folks could use a little bit of help'

It was that experience that gave him the idea to raise money for fellow patients.  He's already raised $24,000, which helps pay for cable TV or internet services for in-patients at the MUHC hematology-oncology unit who can't afford the fees while in hospital.

Rosenberg said while his friends and family were able to visit him often, not every patient has that support.

"I remember a girl that was next to me who just lay there in the dark every day. She was probably 20 years old, losing her hair," he said. "I couldn't help but think these folks probably could use a little bit of help."

So once he was in remission, he decided to help the way he knew best: competing in a feat of strength against some of his strongest friends.

"It's going to be 500 pounds [226 kilograms], and I'm going to do as [many reps] as it takes to win. That's the strongman philosophy," said Rosenberg of his fundraising challenge. 

But don't call it a comeback: he never really left the gym.

Even during his treatment, as soon as Rosenberg was allowed out of hospital, he'd be lifting again, despite concerns from his doctors.

"I had tubes hanging out of my chest. I couldn't do a lot of different things I normally would do," he said. "But you kind of just go with it, and work around it."

While Rosenberg admits that the training itself didn't help his cancer treatment work, he says it did help him "get out in one piece."

"I think he shows he's really dedicated," said Andrew Lutzuk, Rosenberg's friend and mentee at the gym.

"And really stubborn," Lutzuk adds with a laugh. "But I think he needed it, you know? Because it was his outlet. It's how he dealt with stress his whole life."

Rosenberg has recruited Lutzuk and other friends to take part in the challenge and relishes in ribbing them that they'll be competing against "a guy who's older and had leukemia last year."

"He'll always be the winner, you know, at the end of the day," said Lutzuk. "Because he's alive, right?"