Oct. 13, 2010 -- Walking 6 miles or so every week is not only good for the heart, but for the brain, preventing shrinkage and possibly dementia down the road, new research indicates.

“Brain size shrinks in late adulthood, which can cause memory problems,” study researcher Kirk I. Erickson, PhD, of the University of Pittsburgh, says in a news release.

Erickson’s research team examined data on 299 dementia-free people with a mean age of 78 who recorded the number of blocks they walked weekly.

Nine years later, the researchers took brain scans of the participants to measure their brain size. Then, four years later, the participants were tested to see if they had developed cognitive impairment or dementia.
Walking and Brain Volume

Participants who walked at least 72 blocks per week, or between 6 and 9 miles, had more gray matter volume in their brains nine years after the start of the study than people who didn’t walk as much.

By four years later, 116 people, or 40% of participants, had developed cognitive impairment or dementia. Researchers say those who walked the most cut their risk of developing memory loss in half.

The study is published in the Oct. 13 online issue of Neurology.

The findings build on previous research that even moderate exercise can enhance the connectivity of important brain circuits, combating age-related performance on cognitive tests.

“Based on our results, we can conclude that there is a relation between the amount of walking earlier in life and brain volume in later adulthood and that greater volume of tissue related to walking is associated with a reduced risk of cognitive impairment,” the researchers write.

One of the researchers, O.I. Lopez, MD, of the University of Pittsburgh, reports serving on advisory boards for Pfizer, Eisai, and Bristol-Myers Squibb.