Many know that Regular walking keep and fit and healthy but Researchers at the University of Pittsburgh found that men and women who walk at least six miles (about 9.5km) a week are mentally sharper in later life than those who don't walk much.
Our brains, according to the researchers, decrease in size as we age, but regular exercise may protect it in later life and could cut the risks of memory problems by half, the Telegraph reported.
For their study, the team studied 299 dementia free elderly individuals and recorded the distance they walked each week.
For nine years, brain scans were carried out to measure their brain size, and four years further on they were tested for cognitive impairment.
It was found that those who walked at least six to nine miles each week had greater grey matter at the nine year point than those who walked shorter distances. Greater distances did not appear to have any further effect.
Four years later, 116 of the participants, or 40 per cent, were suffering some form of dementia. But those who had walked the most had cut their risk of developing memory problems in half.
Professor Kirk Erickson, who led the the study, said: “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."
“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.”
The new research is published in the medical journal Neurology.