Myths and Misconceptions About Zone 2 with Dr. Brendon Gurd and Kristi Storoschuk

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Zone 2 training has dominated fitness conversations, often positioned as the best path to endurance and fat burning. In the latest Research Hub Podcast, Dr. Karlie Intlekofer speaks with Dr. Brendon Gurd and Kristi Storoschuk from Queen’s University to unpack the science and what it means for performance and programming.

What the Evidence Means for Training

Gurd and Storoschuk examined claims linking Zone 2 training to improved mitochondrial function and fat use. The findings point to a more balanced story than most social media posts suggest.

Exercise performed just below the first lactate threshold, or Zone 2, contributes to cellular signals tied to endurance and metabolism. Yet higher-intensity work consistently produces greater adaptations including stronger aerobic capacity, improved energy use and faster gains in fitness.

For coaches and facility operators, the message is clear: members benefit most from variety. Mixing moderate and higher-intensity sessions across the week creates the foundation for progress that can be measured and sustained.

Dr. Intlekofer notes that if effort feels comfortable for too long, the body may need a new challenge. Shifting intensity is one of the most effective ways to keep clients adapting and engaged.

Mitochondria and Energy

Beyond performance outcomes, intensity drives deeper physiological changes starting with mitochondria.

Dr. Brendon Gurd explains that mitochondria generate energy efficiently and reduce the fatigue that limits performance. “More mitochondria mean you can perform at a higher pace and sustain it longer,” he says.

From a health standpoint, strong mitochondrial function supports insulin sensitivity and overall cardiometabolic health. For aging or sedentary populations, structured training that targets effort can improve both energy levels and daily function, helping people stay active and independent.

Turning Research into Practice

Kristi Storoschuk notes that results come from a range of intensities, not just Zone 2. Continuous sessions above that range can create many of the same benefits as intervals while feeling more approachable for members.

For coaches and facility leaders, this means programming can stay flexible and inclusive, challenging clients at their own pace while maintaining focus on progression.

Key takeaways for effective programming:

• Blend moderate and high-effort training across the week
• Use effort-based cues to guide sessions
• Focus on consistency before increasing intensity
• Reinforce that enjoyment and structure lead to lasting results

Zone 2 remains valuable for building base fitness and recovery, but higher-intensity work drives the biggest changes in performance and metabolic health. Structured programming that blends both creates stronger outcomes for members and clearer success for facilities.

Listen to the full Research Hub Podcast featuring Dr. Karlie Intlekofer, Dr. Brendon Gurd and Kristi Storoschuk for insights you can apply directly to your training programs.