Muscle DNA Changes When We Get Strong, Boosting Effects of Future Workouts

The DNA in our muscles can "remember" periods of growth, new research shows, in a finding that could have consequence for professional athletes who have used steroids to quickly build muscle mass—and laws meant to prevent this.  

A new study published online in Scientific Reports found evidence to suggest that because genes in the muscles become imprinted during growth, it becomes easier for these muscles to grow larger later on. This suggests that individuals who use performance-enhancing drugs may still experience the consequences of large muscle growth in response to exercise years after they stop using the drugs.

For the study, the team looked at the muscle tissue of eight previously untrained male volunteers before and after they were subjected to bouts of exercise training. The team looked at over 850,000 sites on human DNA to see how muscle growth caused by exercise affected the muscle DNA.

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The team was specifically looking for something known as epigenetic changes. This refers to the ability of certain genes being turned on or off due to environmental and behavioral influences. Though we are born with our set of DNA which we inherit, in order for genes in our DNA to influence our biology they must be triggered or "tagged." Recently, researchers have noted that certain behaviors, and experiences, such as exercise can tag these genes.

Upon closer examination the team saw that the genes in the volunteers’ muscles developed epigenetic changes, following growth caused by exercise. However, this wasn’t the only discovery.

01_30_bodybuilding These findings could have consequences for bodybuilders. ROBERTO SCHMIDT/AFP/Getty Images

“These genes remain untagged even when we lose muscle again, but this untagging helps 'switch' the gene on to a greater extent and is associated with greater muscle growth in response to exercise in later life—demonstrating an epigenetic memory of earlier life muscle growth!" explained senior author Adam Sharples of the Cell and Molecular Muscle Physiology at Keele University in a statement.

The researchers suggest their findings could have relevance when establishing rules around performance-enhancing drugs and suspensions . 

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“If the athlete is caught and given a ban—it may be the case that short bans are not adequate, as they may continue to be at an advantage over their competitors because they have taken drugs earlier in life, despite not taking drugs anymore,” explained Robert Seaborne, a PhD study under Sharples who also co-authored the study, in a statement.

Performance-enhancing drugs, also known as doping, are described as any substance used to help build muscle mass and increase athletic performance. These include anabolic steroids, androstenedione, human growth hormone, erythropoietin, diuretics, creatine and stimulants. Steroids are the most widely used, and according to Popular Science, the drug works by supplementing a natural process in the body. Our bodies already use natural steroids to build mass, and taking anabolic steroid simply increases the amount in our bodies, thus increasing the speed of muscle mass.

The team believes that more research is needed before the findings can have real-life applications, either on the court or in the lab, but for the time being they suggest that doping really isn’t as temporary as you might think.