Exercise response varies with genetics

Study Identifies Genes and Mutations Associated with Exercise Traits.

Your parents may be to thank(or to blame) for how your body responds to exercise, and the genes responsible are slowly being identified. That’s one of the conclusions of research published by the American College of Sports Medicine (ACSM.) As presented in the November issue of ACSM’s official journal, Medicine & Science in Sports & Exercise®, the study updates the human gene map for fitness and physical performance.

“Some people are gifted,” said lead researcher Claude Bouchard, Ph.D., FACSM, referring to such characteristics as cardio-respiratory endurance, strength, flexibility, and body composition. Genetics play a big role in such matters, as they do in ‘trainability’ – the capacity to benefit from exercise. ‘But,’ said Bouchard, “there’s no correspondence between the genes responsible for your being advantaged, even as a sedentary person and those allowing you to gain from exercise.”

The study reviewed research published through December 2005 exploring genes and genetic markers linked to performance or fitness. “This compendium,” said Bouchard, “brings into a single source many studies published in a large number of journals around the world. We can begin to see trends and commonalities among the studies.” The first version of the fitness and performance gene map, published in 2001, listed only about one-fifth of the known gene locations mapped in the Bouchard team’s current work.

The study confirmed what had been suggested by earlier research on families and twins: beyond physical traits, there are significant genetic differences in people’s inclination to be physically active.

Likewise, different people may achieve different results from the same activity. Such knowledge has benefits beyond its value as pure science. While the benefits of regular physical activity are well established, said Bouchard, “We’re beginning to see a new area emerge: studies focusing on the role of genetic differences in the inclination to be physically active. Recently, studies have investigated specific genes for their potential contribution to physical activity or the propensity to be sedentary. That’s new; that’s an important line of research.”

An understanding of the role genes play in the inclination to be physically active could make valuable contributions to efforts to improve fitness and health in the general population.

“We haven’t been able to influence people’s behavior to change dramatically their level of physical activity or sedentarism,” said Bouchard. “Compared with the magnitude of the problem, we’ve made very small progress. I contend that there are biological forces that force us back into the same groove when we change from being sedentary to being more active. Those forces are partly determined by our genetic makeup. Thus, research into genetic factors underlying exercise and physical activity levels is a very worthwhile area to pursue from a public health perspective.”

Such research, advocates maintain, deserves more support. While studies of obesity, diabetes, and heart disease receive substantial funding, said Bouchard, relatively little attention is paid to the role of physical activity in maintaining health. He adds that “research should be driven by the need to understand the origin of these diseases taking into account the totality of the factors that may be involved, including genetics, in-utero maternal programming, smoking, nutrition and physical activity, among other factors.”

NOTE: Claude Bouchard, Ph.D., is director of the Human Genomics Laboratory at Pennington Biomedical Research Center in Baton Rough, LA. His collaborators on the gene map study were:

• Molly S. Bray, Ph.D. (Baylor College of Medicine)
• James M. Hagberg, Ph.D. (University of Maryland)
• Louis Pérusse, Ph.D. (Laval University)
• Stephen M. Roth, Ph.D. (University of Maryland)
• Bernd Wolfarth, Ph.D. (Technical University Munich)