Chapter 24 - Genetic Variation in the Response to Exercise Training: Impact on Physical Fitness and Performance

Abstract

There is overwhelming evidence that the response to exercise training, or trainability, varies considerably among individuals and that genetic factors have an important role in explaining the adaptation to exercise training. This review aims to provide a brief summary of the contribution of genetic factors to the trainability of various physical fitness and health-related phenotypes. Evidence from twin and family studies suggests that 20%–50% of variation in trainability could be accounted for by genetic factors. Candidate gene studies and genome-wide screening approaches have been used to identify genomic markers of trainability. A review of candidate gene studies reveals that only five genetic variants with evidence of replication in at least two studies are associated with the response to exercise training. Several genetic variants associated with trainability of phenotypes such as maximal oxygen uptake, submaximal heart rate during exercise, and plasma triglycerides levels have been identified from genome-wide association studies and global gene expression profiling. Finally, there is growing evidence that exercise training influences DNA methylation in different tissues and genes. Although progress has been made in identifying genomic markers associated with the response to exercise training, more research is needed to unravel the molecular basis of trainability and to be able to use genomic markers to predict performance or discriminate between high- and low-responders to exercise training.