Brian Mackenzie

About

American fitness instructor and entrepreneur who is best recognized for having co-founded the Extreme Performance Training program. He is also known for having finished the Angeles Crest 100-mile endurance run. 

Before Fame

He began studying altitude and hypoxic training in 2006.

Trivia

He published a book titled Power Speed Endurance.

Family Life

He married Olympic gold medalist Erin Cafaro MacKenzie. 

Associated With

In March 2017 he posted a photo with fellow fitness instructor Emily Bridgers to his iamunscared Instagram account.