  | HOW WALKING CAN BUILD UP THE BRAIN |
Exercise can freshen and renovate the white matter in our brains, potentially improving our ability to think and remember as we age, according to a new study of walking, dancing and brain health. It shows that white matter, which connects and supports the cells in our brains, remodels itself when people become more physically active. In those who remain sedentary, on the other hand, white matter tends to fray and shrink.
The findings underscore the dynamism of our brains and how they constantly transform themselves & for better and worse; in response to how we live and move.
The idea that adult brains can be malleable is a fairly recent finding, in scientific terms. Until the late 1990s, most researchers believed human brains were physically fixed after early childhood.
But science advanced and revised that gloomy forecast. Studies indicated that some parts of our brains create neurons deep into adulthood, a process known as neurogenesis. Follow-up studies then established that exercise amplifies neurogenesis.
These past studies of brain plasticity generally focused on gray matter, though, which contains the celebrated little gray cells, or neurons, that permit and create thoughts and memories. Less research has looked at white matter, the brain's wiring. Made up mostly of fat-wrapped nerve fibers known as axons, white matter connects neurons and is essential for brain health. But it can be fragile, thinning and developing small lesions as we age . It also has been considered relatively static .
But Agnieszka Burzynska, a professor of neuroscience and human development at Colorado State University in Fort Collins, suspected that science was underestimating white matter. She considered it likely that white matter, like its gray counterpart, could refashion itself, especially if people began to move.
For the new study, published online in June in NeuroImage, she and her colleagues gathered almost 250 older men and women who were sedentary but otherwise healthy. They tested these volunteer; current aerobic fitness and cognitive skills and measured the health of their white matter using a form of MRI brain scan.
Then they divided the volunteers into groups, one of which began a supervised program of stretching and balance training three times a week, to serve as an active control.
Another started walking together three times a week, briskly, for about 40 minutes. And the final group met three times a week to learn line dances and group choreography. All of the groups trained for six months, then returned to the lab to repeat the tests from the study's start.
The walkers and dancers were aerobically fitter, as expected. Even more important, their white matter seemed renewed. In the new scans, the nerve fibers in certain portions of their brains looked larger, and any tissue lesions had shrunk. These desirable alterations were most prevalent among the walkers, who also performed better on memory tests . The dancers, in general, did not.
Meanwhile, the members of the control group showed declining white matter health .
The findings tell us that white matter remains plastic and active, whatever our age, and a few brisk walks a week might be enough, Burzynska says, to burnish the tissue and slow or stave off memory decline.
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