Testing carried out on 299 healthy older people recorded the distances they walked in a week. They were then scanned nine years later to determine the size of their brain and a further four years afterwards to determine whether they were suffering from a decline in mental activity or dementia.

The first test indicated that people who walked between six to nine miles per week had more “grey matter” in their brains than those who did not.

By the time the second set of tests were carried out, 116 of the participants (40%) had developed some form of dementia or cognitive impairment, but those who had walked at least six miles a week were 50% less likely to experience memory problems.

Dr Kirk Erickson, a professor from the University of Pittsburgh who led 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 mid-life 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.”

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Source: Press Association