A Calgary firefighter is pushing his body to the ultimate limit this weekend in support of a sick friend. 

Devin Featherstone is an avid runner and ultramarathon champion who is often seen running the city’s pathways in full firefighter gear, which weighs upwards of 50 pounds. 

He’s participating in the “David Goggins 4x4x48” challenge — a free online event where athletes are encouraged to run four miles every four hours over the course of two days. 

Aside from the daring challenge, Featherstone is raising money for his dear friend Dan Pfaff, who was born with Cystic Fibrosis and has been in hospital for the last 230 days. 

Pfaff has had three double lung transplants, recovery complications and spent six months with family staying in an Airbnb. 

Throughout his treatment, Pfaff’s twin sister has been by his side, while losing her job and livelihood.

Featherstone says the pain experienced while running for hours on end is nothing compared to what those suffering from diseases have to endure. 

“All the money will go directly to his family to help them in this extremely difficult time,” Featherstone wrote in an Instagram post. 

"He is a true warrior and fights each and every day for the simple things. A phenomenal human who loves each day to the fullest and is one of the biggest inspirations to my family.”

Those who wish to donate to the cause can do so online.