Past studies show that those who are most fit have larger brain volume and greater intact white matter, the conductive filler that carries nerve impulses and interconnects the brain, than people who don’t exercise. In this study, scientists in the journal PLoS ONE looked at variable brain activity, measuring blood oxygen level change and brain activity at rest with MRIs to visualize changes. They evaluated each person’s white matter fibers.

Youthful White Matter

“We found that spontaneous brain activity showed more moment-to-moment fluctuations in the more active adults,” said University of Illinois, Champaign-Urbana postdoctoral researcher Agnieszka Burzynska (now a professor at Colorado State University in Fort Collins) who led the study with Beckman Institute for Advanced Science and Technology director Art 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.”

The more active person’s white matter had much more youthful structural integrity.

“We want to know how the brain relates to the body, and how physical health influences mental and brain health in aging,” Burzynska 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.”