You already know that exercise can give you bigger muscles. Now, fascinating new research involving identical twins suggests it can do the same for your brain.
A small-scale study showed that twins who worked out regularly had significantly more gray matter -- especially in the regions of the brain involved in motor control -- than their twins who exercised less. Since the twin pairs had grown up in the same environment (and, of course, shared the same genetic makeup), it seems likely that their exercise habits and not some other factor accounted for the difference in brain volume.
"We were somewhat surprised that so clear change in brain structure occurred as a result of differences in exercising during adulthood, as the exercise habits of these twin pairs were similar during childhood," Dr. Urho Kujala, a professor of sports and exercise medicine at the University of Jyvaskyla in Finland who oversaw the study, told The Huffington Post in an email.
Got twins? For the study, the researchers analyzed the body compositions, insulin levels, and MRI brain scans of 10 pairs of young adult identical twin brothers. In each pair, one of the twins indicated in a questionnaire that he exercised regularly on his own while the other twin didn't.
"On average, the more active members of twin pairs were jogging three hours more per week compared to their inactive co-twins," Kujala told HealthDay.
While the twins' individual exercise routines differed, there were no major differences in their diets, The New York Times reported.
Big benefits. The researchers found that the twins with regular exercise routines had less body fat, healthier insulin levels, and indeed larger volumes of gray matter in the brain's striatal and prefrontal cortex. More gray matter is a good thing, since it's where information from sensory and motor neurons are processed in the brain.
"Such changes would likely result in improved functional mobility as one ages," Dr. Cedric Bryant, chief science officer for the American Council on Exercise, who was not involved in the study, told The Huffington Post. "It would be interesting to see if the inactive twins were to become more physically active how long it would take, if at all, for them to experience similarly positive outcomes as the active twins."
Brains and brawn. This isn't the first time research has shown that going hard in the gym may be good for your brain. A 2014 study, for instance, suggests that weightlifting for as little as 20 minutes can boost your long-term memory by around 10 percent. Nice.
Kujala said in the email that he and his research team plan to continue to analyze and report more detailed results on how exercise influences brain function.
The new study was published in the March 2015 edition of the journal Medicine & Science In Sports & Exercise.