Do Genetics Influence Exercise Capacity and Trainability?

Do Genetics Influence Exercise Capacity and Trainability?

John Quindry, Ph.D., FACSM |  Oct. 8, 2018

This is part nine of a series of blogs from attendees at ACSM's Conference on Integrative Physiology of Exercise. The following blog is a reflection on the debate titled "Do genetics influence exercise capacity and trainability?"written by Dr. John Quindry.

If you didn’t happen to witness the debate between Claude Bouchard, Ph.D., FACSM, and Michael Joyner, M.D., FCASM, titled “Do genetics influence exercise capacity and trainability?” you missed an event to behold. This debate was arguably the highlight of ACSM’s Conference on Integrative Physiology of Exercise in San Diego.

The two pillars of exercise science, Bouchard and Joyner, sparred on three questions:

1) genetic causation of exercise capacity,

2) the genetic influence on trainability, and

3) why is it so hard to pin down the respective genetic signatures.

On all three pre-arranged topics the debate was lively.

Given the scientific positions of a physician-physiologist and a geneticist, the arguments were prescribed by their unique perspectives. Dr. Bouchard provided clear examples from mouse strains, low/high volume rats and human twin studies that reinforce the fact that 40 to70 percent of exercise capacity is genetically heritable. By virtue of his approach, Bouchard’s arguments were at the “40,000 foot” level, whereas Dr. Joyner’s were at ground level – asking pointedly, “where are the genetic weeds” to verify these claims? Stated differently, Joyner’s arguments were of the holistic physiologist variety and centered on the fact that understanding of exercise capacity and trainability are irreducible in terms of identifying causative gene variants. Both agreed that the matter is far more complex than has long been predicted by medical science.

Who won?

Opinions differ, but I’d call it a draw. In terms of debate form, I’d give Bouchard the edge on exercise capacity and Joyner the edge on trainability. Like many in attendance, I flip-flopped on topic three, favoring whoever was at the microphone. But you want me to pick a side, and since Joyner was the last to speak I’ll say that he may have won…by a genetic hair. As Joyner stated in his closing argument, “context is everything.” Given that both scientists provided the strongest of evidence-based positions, the lesser talented me prefers the guiding hand of nurture.

Given their stature as gentlemen scientists, neither Bouchard nor Joyner took a cheap shot. But then again, neither backed down. The best barb of the day definitely goes to Bouchard when he quipped to Joyner – known for repeatedly calling mechanistic science to task – “to solve these matters we have to indulge extensively in the sin of reductionism.” Pure gold! What may have been missed by those of us that are peripheral to the debate is the fact that big data analyses, and recently heralded approaches such as GWAS and SNP analyses, have recently lost stock value for an inability to reveal causative links between the genetic code and exercise outcomes.

Don’t miss out when this debate unfolds a second time in a contrasting perspective to be featured in a future issue of Medicine and Science in Sports and Exercise.

Read part 1 of this series: "Can Exercise Fill the Reductionist Gap? Reflections on Dr. Michael Joyner's Keynote."
Read part 2 of this series: "Are Exercise 'Mimetics' a Realistic Substitute for Exercise Training? Reflections on the Debate." 
Read part 3 of this series: "Exercise and Energy Restriction to Improve Health: Recent Research." 
Read part 4 of this series: "Molecular Transducers of Physical Activity (MoTrPac) Update." 
Read part 5 of this series: "Metabolic Flexibility in Health & Disease: A Symposium Summary." 
Read part 6 of this series: "How Exercise Promotes Brain Health in Aging." 
Read part 7 of this series: "Molecular Transducers of Exercise-Induced Muscle Hypertrophy: A Symposium Summary." 
Read part 8 of this series: "Exercise Pressor Reflex Function in Health and Disease." 

John Quindry, Ph.D., FACSM, is a member of the faculty at the University of Montana, Department of Health and Human Performance. He served as a co-planner of ACSM's Conference on Integrative Physiology of Exercise.