Seniors who regularly walk around 10 kilometres per week suffer less brain shrinkage, which may help stave off dementia, researchers have found.
Brain size shrinks in late adulthood and can cause memory problems. Studies suggest that activities like walking preserve brain volume, but U.S. researchers wanted to test if seniors who walk more are better able to fight off dementia.
In the study, 299 volunteers in Pittsburgh with an average age of 78 who were free of dementia recorded the number of blocks they walked in one week. Then nine weeks later, scientists took brain scans of the participants to measure their brain size.
After four more years, researchers tested the subjects to see if they had developed dementia or other memory problems.
Study author Kirk Erickson of the University of Pittsburgh and his co-authors found that people who walked at least 72 blocks per week — 10-14 kilometres — showed greater grey matter volume in their brain compared with people who didn't walk as much.
"Our results are in line with data that aerobic activity induces a host of cellular cascades that could conceivably increase grey matter volume," the study's authors wrote.
Trekking more than 72 blocks did not seem to offer any further increases in grey matter volume, the researchers found.
The findings held true regardless of other risk factors such as family history.
Erickson's team called for more studies on the effects of exercise on dementia, but noted that in the absence of effective treatments for Alzheimer's that walking could help.
"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," Erickson said.
The study appears in this week's online issue of the journal Neurology.
The study was funded by the U.S. National Institute on Aging.
Read more: http://www.cbc.ca/health/story/2010/10/15/walking-dementia-brain.html#ixzz12UZruk4o