Endurance runners display greater connections between different brain regions than more sedentary people.
Previous research has shown that training for a long time in activities that require accurate fine motor control - such as learning to play a musical instrument - alter the structure of brain areas that are connected with motor function.
These fine motor activities also appear to cause changes in cortical areas that are involved in sensory, spatial, and attentional processes.
Additionally, people who are skilled in activities that require high levels of hand-eye coordination - such as golf, gymnastics, and racquet sports - also experience altered brain structure and function.
The University of Arizona (UA) researchers note that up until now, there have been few studies that have explored the effects that repetitive athletic activities requiring little motor control precision - including long-distance running - can have on the brain.
To further investigate, UA running expert David Raichlen, an associate professor of anthropology, co-designed a study with UA psychology professor Gene Alexander - who studies brain aging and Alzheimer's disease as a member of the UA's Evelyn F. McKnight Brain Institute.
Brain changes associated with endurance running examined
"These activities that people consider repetitive actually involve many complex cognitive functions - like planning and decision-making - that may have effects on the brain," says Raichlen.
Raichlen, Alexander, and collaborators aimed to examine the changes in the brain associated with endurance running - a sport that involves repetitive rather than complex fine motor skills. The results of the research were published in the journal Frontiers in Human Neuroscience.
The team conducted the study by comparing the magnetic resonance imaging (MRI) brain scans of adult male cross country runners, alongside adult males who have not engaged in regular physical activity for at least a year. The participants were aged between 18-25 years and had similar body mass index and education levels.
The MRI scans captured the processes that occur in the brains of participants while they were awake and not engaging in any specific tasks.
Overall, the results showed that compared with the more sedentary individuals, the runners displayed greater connections between different regions in several areas of the brain. One of these areas, the frontal cortex, is important for cognitive functions, including the ability to switch attention between tasks, planning, and decision-making.
The new research sheds light on how exercise can affect the brain, particularly in young adults. However, further research is needed to work out if the physical differences in brain connectivity can contribute to differences in cognitive functioning.
Being active as a young adult could protect against aging, disease
"One of the things that drove this collaboration was that there has been a recent proliferation of studies, over the last 15 years, that have shown that physical activity and exercise can have a beneficial impact on the brain, but most of that work has been in older adults," says Raichlen.
"This question of what's occurring in the brain at younger ages hasn't really been explored in much depth, and it's important," Raichlen continues. "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."
"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. 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."
Alexander notes that, as individuals age, functional brain connectivity seems to change - particularly in people who have Alzheimer's or other neurodegenerative diseases. Learning about the brains of young adults could potentially help with the prevention of the cognitive decline that occurs with age, he concludes.