By Elise Craig
It doesn’t take a genius to realize that exercise can reshape our bodies. But working out can also change our DNA, and researchers are slowly discovering how the change occurs.
When people who don’t work out regularly get their bodies moving with acute exercise, the DNA in their muscle fibers is chemically modified, researchers are reporting in the March issue of Cell Metabolism.
The changes don’t actually alter our DNA sequence—the AGTC base pair combination, which is identical in all the cells of a human body, stays the same. But, the researchers found, the chemical marks above the sequence are chemically and structurally altered at precise locations.
These modifications won’t change the sedentary into superheroes, but they can turn certain genes on. That can start the process of building new proteins, which can help our bodies break down fat and sugar for energy more efficiently, said Juleen Zierath of Karolinska Institutet in Sweden, an author of the study.
“In a sense,” Zierath said, “they may make it easier for us to exercise the next day.”
Over time, she added, the muscle would adapt to “cope with the demands of long-term exercise.”
Scientists have been long aware that exercise can affect gene expression, said Dr. Stephen M. Roth, associate professor of kinesiology at the University of Maryland who studies exercise and DNA. “The novelty here is that we are now beginning to understand the mechanisms behind these changes in gene expression.”
The research is part of a broader look into the way that genes, obesity and related illnesses are affected by exercise and other factors. “It’s another piece of a very complex puzzle,” said Ruth Loos, a genetic epidemiologist at Mount Sinai School of Medicine in New York. “Once we understand the biology, we can develop treatment, maybe drugs. But that’s a very long-term process.”
Though the researchers did not study the DNA of die-hard exercisers, Zierath said, there is evidence to suggest that they will also see their DNA modified as they work out—to the same extent as their more sedentary counterparts.
The scientists also found that caffeine can mimic these same effects.
But that doesn’t mean you should hop on the treadmill with a cup of coffee. The scientists exposed cells to caffeine in a dish, and aren’t sure how much java it would take to mimic the effects of exercise on our DNA. “It doesn’t mean that a cup of coffee has the same effects as an hour-long workout,” Zierath said.
What’s more, she added, the amount of coffee required “would certainly lead to caffeine intoxication,” symptoms of which can include muscle twitching and anxiety—even irregular heartbeat.
But, Zierath believes, far down the line these findings could help scientists figure out a way to treat patients who are unable to work out.
“In the future, we might be able to develop strategies to induce chemical modifications on the DNA in muscles to mimic the benefits of exercise,” she said.
But those who hate to exercise shouldn’t expect to slam back pills instead of hitting the bike trail–exercise isn’t just a means to help improve our muscles.
Other treatments “can’t completely replace exercise, because it has many other effects, like cardio-respitory fitness,” Loos said.