As humans age, the brain’s ability to process information with speed and efficiency steadily declines. But a team of researchers from the University of Illinois have found in a new study, published in Frontiers in Aging Neuroscience, that higher levels of fitness can curb cognitive decline in older adults by increasing the volume of key parts of the brain, particularly those responsible for reasoning and problem solving.

"This research adds to our growing understanding of the relationship among physical activity and cognitive and brain function and suggests that we can improve our brain health by changing our lifestyle even as we age,” said the study’s lead researcher Art Kramer, director of Beckman Institute’s Biomedical Imaging Center at the University of Illinois, in a press release.

Previously, researchers have studied how exercise affects behavior in older adults, and additional studies have looked into how exercise affects brain function. But, according to Wong, this is the first study to examine how the three elements work together. Researchers examined the brain images of 128 adults between the ages of 59 and 80, and focused specifically on the areas of the brain that were activated as participants performed tasks.

First, participants were asked to walk slightly faster than their normal pace while medical personnel tracked their oxygen uptake, heart rate, and blood pressure. Next, they were asked to either raise their right index finger when they saw the letter “A,” their right middle finger when they saw the letter “B,” their left index finger when they saw the number “2,” or their left middle finger when they saw the number “3” on a screen.

When they were asked to walk and respond to the letters or numbers on the screen at the same time, it represented a dual-task process in which they were partaking in cardiorespiratory fitness and active thought. When researchers reviewed their brain scans, it revealed the anterior cingulate cortex and the supplementary motor area were engaged when participants were asked to exercise. These regions enhanced the higher executive functions of the brain, which are responsible for conflict monitoring, multitasking, and dual-task processing.

"We looked at dual-task specifically because it's a measure of executive function, which is required for multiple cognitive processes, such as working memory, task management, coordination, and inhibition," said the study’s co-author Chelsea Wong, a medical student at the University of Illinois, in a press release. "We know that as people age, executive function declines, so we found that with higher cardiorespiratory fitness, you can enhance executive function performance behaviorally, as well as executive function-related brain activation."

According to the Centers for Disease Control and Prevention, regular physical activity is one of the most important things an older adult can do for their health. Adults 65 years and older need at least 150 minutes of moderate- to vigorous-intensity aerobic activity, such as brisk walking, in addition to muscle-strengthening activities at least twice a week, such as weightlifting.

Experts from The National Institute on Aging have gone as far as saying the elderly population is harming themselves if they don’t exercise. Last year, research published in the British Journal of Sports Medicine has found exercise increases the size of another region in the brain involved in memory and learning. That said, increasing exercise levels could ultimately be a potential way to curb dementia rates worldwide.

Source: Kramer AF, Wong CN, Chaddock-Heyman L, et al. Brain activation during dual-task processing is associated with cardiorespiratory fitness and performance in older adults. Frontiers in Aging Neuroscience. 2015.