You've now one more reason to get up off the couch in the new year:  MRI scans show that the brains of those who exercise have greater functional connectivity than the brains of more sedentary individuals.

The study looked at brain scans of young cross country runners and compared them to those of young adults who engage in very little exercise. The connections between the distinct brain regions of the runners were greater in the runners' brains. Notably included was the frontal cortex, which handles planning, decision-making and the ability to switch attention between tasks.

More research will be needed to determine what effect the differences in brain connectivity have on cognitive functioning, but the current data lay the groundwork for researchers to better understand how exercise affects the brain. Also important is the fact that this study involved young people; most research regarding exercise and brain function is focused on Alzheimer's disease, and therefore has a much older study group.

"This question of what's occurring in the brain at younger ages hasn't really been explored in much depth, and it's important," said David Raichlen, an associate professor of anthropology the University of Arizona and co-designer of the study. "Not only are we interested in what's going on in the brains of young adults, but we know that there are things that you do across your lifespan that can impact what happens as you age, so it's important to understand what's happening in the brain at these younger ages."

Previous studies have shown how activities that require high levels of hand-eye coordination, like golf, or fine motor control, such as playing the piano, can alter brain structure and function. But surprisingly little research has been done that shows the effect thatrepetitive athletic activities that do not require much precise motor control – such as running – have on the brain.

"One of the key questions that these results raise is whether what we're seeing in young adults -- in terms of the connectivity differences -- imparts some benefit later in life," said UA psychology, neuroscience and physiological sciences professor Gene Alexander. "The areas of the brain where we saw more connectivity in runners are also the areas that are impacted as we age, so it really raises the question of whether being active as a young adult could be potentially beneficial and perhaps afford some resilience against the effects of aging and disease."

The study was published in he journal Frontiers in Human Neuroscience.