Physical activity's mental component
By STEPHEN NOHLGREN
Published February 27, 2007
Work that Sudoku puzzle if you like, but don't forget to eat your vegetables and take a walk.
In a nutshell, that's the advice Alzheimer's researchers gave in interviews about how personal habits might affect the disease.
"The No. 1 things if you want to prevent this disease are the same things that work for heart disease," says Harvard neurology professor Rudolph Tanzi. "Watch your diet, don't become obese and exercise."
Recent news reports have touted brain teasers and puzzles as preventives. And certainly, higher levels of education are associated with lower levels of Alzheimer's, as are careers such as law and education.
But none of these habits and choices has proved as directly beneficial as exercise, says Ross Andel, assistant professor of aging studies at the University of South Florida.
Exercise "probably creates more blood vessels in the brain," Andel says, "and getting more blood in the brain keeps the brain healthier."
Exercise also helps people keep their weight under control, important because high body masses are associated with increased prevalence of Alzheimer's.
Beta-amyloid, a protein thought by many to trigger the disease, accumulates more in brains of inactive lab mice than in mice that have ready access to running wheels and stimulating tunnel mazes.
That increase in activity seems to work in humans, too.
A nine-year study in Washington state showed that people who walked at least 15 minutes a day, at least three times a week, developed significantly less Alzheimer's than people who did not exercise.
Good news for couch potatoes: Five walks a week worked better than three, but strenuous exercise did not seem to impart any extra benefit.
Neither exercise nor any other lifestyle choice will prevent Alzheimer's, Andel says. But exercise and a healthful diet can delay symptoms.
"Maybe you are genetically predisposed to develop it at 85," Andel says. "But with a good lifestyle you are now postponing it until 90."