Brian MacKenzie is a human performance specialist, endurance coach, and author known for his work on breathing, resilience, and high-performance training. Over the past two decades he has worked with elite athletes, Special Forces operators, and high-level performers across multiple disciplines.

In this episode, Brian explains how breathing influences performance, stress tolerance, and recovery. The conversation explores how modern training methods overlook fundamental human systems, why breath control plays a central role in endurance and resilience, and how learning to regulate stress can dramatically improve both physical and cognitive performance.

Justin and Brian also discuss the evolution of endurance training, the psychology of pushing limits, and how performance principles used by elite operators and athletes can apply to everyday life.