Walking at least six miles a week can protect brain size and, in turn, preserve memory in old age, according to the findings of a new study published in the medical journal Neurology.
“Brain size shrinks in late adulthood, which can cause memory problems. Our results should encourage well-designed trials of physical exercise in older adults as a promising approach for preventing dementia and Alzheimer’s disease,” stated lead author Kirk. I. Erickson, PhD, of the University of Pittsburgh.
In the study, 299 people without dementia recorded the number of blocks they walked in one week.
Nine years later, scientists took brain scans of the participants in order to measure their brain size.
Four years after that, participants were tested to determine if they had developed cognitive impairment or dementia.
Researchers found that people who walked at least 72 blocks a week, the equivalent of six to nine miles, had more gray matter volume than people who walked less.
Walking more than 72 blocks didn’t seem to increase gray matter volume any further.
Four years after the initial brain scans, 116 or 40 percent of the participants had developed cognitive impairment or dementia.
Those who walked the most cut their risk of getting memory problems in half.
“If regular exercise in midlife could improve brain health and improve thinking and memory in later life, it would be one more reason to make regular exercise in people of all ages a public health imperative,” said Erickson.
The study was supported by the National Institute on Aging and reported in Science Daily.