Table of Contents
- Introduction
- Guest Information
- Timestamps
- Related Resources
- Premium Content
- Detailed Study Notes
- Transcript
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Introduction
In recent years “Zone 2 training” has gained immense popularity in fitness and health circles, often being proclaimed the “best” cardiovascular training for metabolic health. Zone 2 training is sustained, low-intensity exercise below the lactate threshold that is commonly employed by many elite level endurance athletes, with a variety of proposed performance benefits. This led to interest from health-conscious folks about its ability to improve markers like VO2 max and mitochondrial function, which are associated with better health outcomes and longevity.
Prof. Brendon Gurd, an exercise physiologist at Queen’s University, is the co-author of a recent review published in Sports Medicine that examined some of the claims made around zone 2 training and health in the general population.
This episode looks at whether the evidence truly supports Zone 2 as a uniquely effective training zone or if this hype has outpaced the research. These insights help professionals and individuals make evidence-based recommendations and avoid unintended negative consequences of following certain ideas.
Guest Information

Prof. Brendon Gurd
Dr. Brendon Gurd is a Professor in the School of Kinesiology and Health Studies at Queen’s University, where his research focuses on exercise physiology and skeletal muscle adaptation. His work explores how different intensities and types of exercise influence mitochondrial content and function in muscle tissue, with the goal of understanding how to optimize health and performance through training.
He leads the Queen’s Muscle Physiology Lab and has published extensively on high-intensity interval training (HIIT), mitochondrial biogenesis, and exercise-induced molecular signaling. Dr. Gurd is widely respected for his evidence-based approach to examining training methodologies and their real-world applications.
Timestamps
- [03:23] Discussion with Professor Brendan Gerd
- [05:56] Zone two training: Mechanisms and misconceptions
- [10:56] Practical applications and recommendations
- [22:16] Research gaps and future directions
- [35:47] Key ideas segment (Sigma Nutrition Premium)
Related Resources
- Join the Sigma email newsletter for free
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- Enroll in the next cohort of our Applied Nutrition Literacy course
- Review paper: Storoschuk et al., 2025 – Much Ado About Zone 2: A Narrative Review Assessing the Efficacy of Zone 2 Training for Improving Mitochondrial Capacity and Cardiorespiratory Fitness in the General Population
- Lecture Slides: Prof. Brendon Gurd – Is Zone 2 the optimal intensity for inducing mitochondrial adaptation?
Premium Content
- Detailed study notes
- Transcript
- Lecture Slides: Prof. Brendon Gurd – Is Zone 2 the optimal intensity for inducing mitochondrial adaptation?
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