How walking can build the brain

These previous studies on brain plasticity have generally focused on the gray matter, which contains the famous small gray cells, or neurons, which allow and create thoughts and memories. Less research has looked at the white matter, the brain wiring. The white matter is made up largely of fat-coated nerve fibers known as axons and connects nerve cells and is essential for brain health. But they can be fragile, mild and progressive lesions as we age and are ravages that can prevent cognitive decline. It is also worrying that it has been considered relatively fixed, with little flexibility or adaptability as our lives change.

But Agnieszka Burzynska, a professor of neuroscience and human development at Colorado State University in Fort Collins, suspected that science underestimated the white matter. “She was like an ugly and neglected step-sister” to Gray Matter, she says, being ignored and misjudged. She believed that white matter was likely to have as much plasticity as its gray counterpart and be reshaped, especially if people began to move.

So, for the new study, published online in June in NeuroImage, she, graduate student Andrea Mendes Colmenares and other colleagues set out to process people’s white matter. They started by collecting about 250 elderly men and women who were stable but otherwise healthy. In the laboratory, they tested the volunteers’ aerobic capacity and current cognitive abilities and also measured the health and function of the white matter, using a sophisticated form of brain MRI.

They then divided the volunteers into groups, one of whom began a supervised stretching and balance exercise program three times a week to serve as active control. Another started walking together three times a week abruptly for 40 minutes. The last group took over the dance, meeting three times a week to learn and practice line dances and group choreography. All groups trained for six months, then returned to the laboratory to repeat the tests at the beginning of the study.

And scientists have found that their bodies and brains have changed for many. The walkers and dancers were much more suitable than expected. Most importantly, their white substance looked fresh. In the new scans, the nerve fibers in certain parts of their brain appeared larger and any tissue damage was reduced. These desirable changes have become more prevalent among walkers, who have now performed better on memory tests. Dancers generally didn’t.

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