San Diego Union-Tribune

RESEARCH SHOWS POWER EXERCISE HAS IN PUMPING UP BRAIN FUNCTION

- BY GRETCHEN REYNOLDS

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 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 and inflexible after early childhood. We were born, it was thought, with most of the brain cells we would ever have and could not make more. In that scenario, the structure and function of our brains would only decline with age.

But science advanced, thankfully, and revised that gloomy forecast. Complex studies using specialize­d dyes to identify newborn cells 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. When rodents run, for example, they pump out three or four times as many new brain cells as inactive animals, while in people, beginning a program of regular exercise leads to greater brain volume. In essence, this research shows, our brains retain lifelong plasticity, changing as we do, including in response to how we exercise. 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,

The idea that adult brains can be malleable is a fairly recent finding, in scientific terms.

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