Epigenetics is the study of how genetic blueprints are turned into proteins, a process called gene expression, and how this process is regulated to create dynamic variations in levels of protein production. Protein production shifts in response to diet, environment, aging, and other factors, and can have a large impact on long-term health. The practice of calorie restriction produces sweeping epigenetic changes for example, leading to significantly longer healthy lives in laboratory animals.
Here researchers review work on the epigenetics of exercise in humans. Cataloging epigenetic alterations that occur in response to exercise is an early step on the road to trying to reproduce these changes using drugs or other techniques. At some point it will be possible for all of us to have optimal operation of metabolism for long-term health without actually undertaking exercise or calorie restriction or having good genes. But it is worth considering that this outcome is still a long way distant, and the old-fashioned methods of achieving the same goals are free, proven, and presently available to everyone.
Most human phenotypes are influenced by a combination of genomic and environmental factors. Engaging in regular physical exercise prevents many chronic diseases, decreases mortality risk and increases longevity. However, the mechanisms involved are poorly understood. The modulating effect of physical (aerobic and resistance) exercise on gene expression has been known for some time now and has provided us with an understanding of the biological responses to physical exercise.
Emerging research data suggest that epigenetic modifications are extremely important for both development and disease in humans. In the current review, we summarise findings on the effect of exercise on epigenetic modifications and their effects on gene expression. Current research data suggest epigenetic modifications (DNA methylation and histone acetylation) and microRNAs (miRNAs) are responsive to acute aerobic and resistance exercise in brain, blood, skeletal and cardiac muscle, adipose tissue and even buccal cells. Six months of aerobic exercise alters whole-genome DNA methylation in skeletal muscle and adipose tissue and directly influences lipogenesis. Some miRNAs are related to maximal oxygen consumption (VO2max) and VO2max trainability, and are differentially expressed amongst individuals with high and low VO2max.
Remarkably, miRNA expression profiles discriminate between low and high responders to resistance exercise (miR-378, -26a, -29a and -451) and correlate to gains in lean body mass (miR-378). The emerging field of exercise epigenomics is expected to prosper and additional studies may elucidate the clinical relevance of miRNAs and epigenetic modifications, and delineate mechanisms by which exercise confers a healthier phenotype and improves performance.