Walking could protect brain against shrinking, US research says
Martin Wainwright
13 October 2010
The historian George Macaulay Trevelyan wrote ∈1913 that he had two doctors: "My left leg and my right". Now a report appears to show that the simple medicine of putting one foot ∈ front of another is a potential defence against dementia and Alzheimer's.
Walking may protect the brain against shrinking and preserve memory ∈ the elderly, according to research by US neurologists who monitored 300 volunteers over 13 years. The US study bears this out, with neurological tests on dementia-free people ∈Pittsburgh who agreed to log their walks and accept brain monitoring ∈1995. Tests nine years later, followed by a further round ∈2008, showed that those who walked the most cut their risk of developing memory problems by half.
The study suggests that nine miles a week -- or ∈ the urban US terms of the data, 72 Pittsburgh city blocks -- is the optimum distance for "neurological exercise". The paper, published ∈Neurology, the online medical journal of the American Academy of Neurology, found no discernible bonus ∈ going the extra mile after that.
The first round of scans showed that nine-mile walkers had larger brains than those who walked around for less. After a further four years, 116 volunteers -- 40% of the sample -- had developed some dementia or cognitive impairment, with the effects 50% greater on those who walked only short distances and on non-walkers. "Our results should encourage well-designed trials of physical exercise ∈ older adults as a promising approach for preventing dementia and Alzheimer's disease," Dr Kirk Erickson, of Pittsburgh University, who led the study, said. "Brain size inevitably shrinks ∈ late adulthood, which can cause memory problems. So, if regular exercise ∈ midlife could improve brain health, thinking and memory ∈ later life, it would be one more reason to make regular exercise ∈ people of all ages a public health imperative."
Trevelyan, who lived to the age of 84, was a pioneer of youth hostelling and the national parks who bought five farms ∈Langdale to preserve the beauty of that part of the Lake District. Among his many other comments on his hobby was: "After a day's walking, everything has twice its usual value." His enthusiasm was shared by the Danish philosopher Soren Kierkegaard, who wrote: "Above all, do not lose your desire to walk. Every day I walk myself into a state of well-being and walk away from every illness." Ralph Waldo Emerson, too, put his health down to shoe leather, writing: "I measure your health by the number of shoes and hats and clothes you have worn out."
The study
