Researchers have known that people who are physically active tend to have larger brain volumes and more intact white matter than those who are sedentary.
Now a new study by researchers at the University of Illinois shows that physically fit older people have greater cognitive flexibility. Specifically, they found that older adults who regularly participate in moderate to vigorous physical activity have more variable brain activity while at rest than those who don’t. This brain variability is connected with better cognitive performance, say the researchers.
“Our study, when viewed in the context of previous studies that have examined behavioral variability in cognitive tasks, suggests that more-fit older adults are more flexible, both cognitively and in terms of brain function, than their less-fit peers,” said researcher Art Kramer, Ph.D., director of the Beckman Institute for Advanced Science and Technology.
For the study, the researchers monitored 100 older adult participants between the ages of 60 and 80 with accelerometers (an instrument used to measure acceleration). This tool enabled researchers to objectively measure the participants’ physical activity during the week.
The researchers also used functional MRI to analyze how blood oxygen levels changed in the brain over time, reflecting each participant’s brain activity at rest. They also evaluated the microscopic integrity of each person’s white-matter fibers, which carry nerve impulses and interconnect the brain.
“We found that spontaneous brain activity showed more moment-to-moment fluctuations in the more-active adults,” said University of Illinois postdoctoral researcher Agnieszka Burzynska, Ph.D., who conducted the study with Kramer.
“In a previous study, we showed that in some of the same regions of the brain, those people who have higher brain variability also performed better on complex cognitive tasks, especially on intelligence tasks and memory,” added Burzynska, now a professor at Colorado State University.
The researchers also found that, on average, older adults who were more active had better white-matter structure than their less-active peers.
The new research highlights yet another way to assess brain health in aging, Burzynska said.
“We want to know how the brain relates to the body, and how physical health influences mental and brain health in aging,” she said.
“Here, instead of a structural measure, we are taking a functional measure of brain health. And we are finding that tracking changes in blood-oxygenation levels over time is useful for predicting cognitive functioning and physical health in aging.”
The new findings are published in the journal PLOS ONE.