An Anti-Alzheimer's Workout
None of the new brain stimulation gadgets hit that most worrisome of disorders, Alzheimer's disease. Quite simply and sadly, no one understands the snarl of neural circuits disrupted in the 4.5 million Alzheimer's patients well enough to figure out where to plant an electrical device that might fix them.
Yet another kind of stimulant may help prevent the disease: physical exercise. New studies indicate that what's good for your heart is also good for your head. Last month one showed that 15 minutes of walking, biking, or even stretching, three times a week, cuts the risk of dementia by at least a third. "And the nice thing is that we're talking about modest exercise, not two hours in the gym every day," says Dallas Anderson, a dementia expert at the National Institute on Aging.
Workouts have been shown to reduce other ailments of aging such as hypertension and heart disease. And several small studies have hinted that benefits extend above the neck. They've linked lower exercise levels when people are first observed to higher rates of dementia many years later.
But there's been a problem with connecting the research dots this way. Dementia starts subtly, years before a clinical diagnosis. Alzheimer's and major depression go hand in hand; a study published last week shows that patients with both diseases had exceptionally high amounts of brain damage. Brain and mood problems may lead people to abandon things like exercise. So people who started out with low exercise levels may have already been sick--although researchers didn't know it--and they ended up sicker. In other words, dementia affects exercise levels, not the other way around.
The newest such research, however, went to great pains to avoid this problem. Eric Larson and his colleagues at Group Health Cooperative in Seattle, Wash., measured the mental health of more than 1,700 elderly people every which way to weed out ailments. After following them for six years, the researchers discovered that people doing modest but regular exercise were 30 to 40 percent less likely to develop dementia than nonexercisers.
Exercise might keep people from losing their minds as it keeps them from losing heart: by improving circulation. It reduces the chances of blood vessel blockage. And exercise might even foster the growth of new brain cells just as it promotes cell growth elsewhere in the body, Anderson suggests.
Brainteasers. What about mental workouts? Keeping your brain sharp with things like crossword puzzles and Sudoku has become a popular notion. But "I think this idea may have been oversold," says Margaret Gatz, a psychologist specializing in dementia at the University of Southern California. "There are hints, but the evidence isn't very solid."
Oft-cited long-term studies of nuns, for example, link better writing skills as young adults to lower Alzheimer's rates 50 years later. But they may have had higher IQs to start with, or better social relationships to reduce stress, or been more physically active--all sorts of factors that may strengthen the brain. "It may, in fact, be a whole constellation of things that helps," says Ross Andel, a gerontologist at the University of South Florida in Tampa. Focusing on something like a puzzle may miss the larger picture--and all of the health benefits.
This story appears in the February 20, 2006 print edition of U.S. News & World Report.
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