Rx for the Brain:Move

That8217;s hopeful news for many who worry that growing old may mean losing their minds.

A 2006 survey conducted by Harris Interactive for the MetLife Foundation found that Alzheimer8217;s was a bigger source of anxiety for people above 55 years in age than heart disease, stroke and diabetes.

8220;Losing one8217;s mental faculties is the biggest fear,8217;8217; said Shawn Brennan, who specialises in promoting senior health initiatives for Montgomery County8217;s Department of Health and Human Services. 8220;Whenever we have an event focusing on improving your memory, people just flock to it.8217;8217;

Dorothy Mudd, 80, of Chevy Chase has heard enough to change her habits. Her goal is be physically and mentally fit, so six months ago she hired a personal trainer. She was sore at first, but within a few months, she says, she felt stronger 8212; and mentally sharper.

In a six-year study of 1,740 adults 65 and older published last year in the Annals of Internal Medicine, researchers found those who exercised more than three times a week were less likely to develop dementia than those who didn8217;t. A 2005 study of 3,375 adults in the same age group produced similar results. But investigators said the findings, while encouraging, don8217;t yet prove that exercise prevents the onset of dementia.

Scientists believe aerobic exercise increases activity in the frontal regions of the brain that control 8220;executive functions8221;: working memory, multi-tasking and the ability to sort and screen out distractions. The findings are especially promising because these are the areas of the brain most vulnerable as people age, researchers say.

8220;Exercise can help turn off the death march of cells both in our bodies and our brains,8217;8217; Ratey said. Designing research to test the possible effect of exercise on specific brain functions, however, can be tricky.

For one study published this year, Bradley Hatfield, a professor of kinesiology and sports psychology at the University of Maryland and fellow researchers devised tests of mental skills: In one, they asked 120 seniors to distinguish quickly between a series of auditory tones; in another, the seniors had to sort through conflicting visual information. Hatfield and his team found that physically active participants showed 8220;more vigorous8221; responses to the tests than others. Technological advances are also letting scientists monitor changes in the brain.

In a study published in 2006, a team of researchers from the University of Illinois at Urbana was among the first to use functional magnetic resonance imaging, a neuroimaging technique, to show changes in the brains of subjects they studied. Those who took part in aerobic exercise showed the largest change in brain volume, particularly in the frontal areas of the brain associated with memory, the study showed.

Arthur Kramer, a professor of neuroscience who was part of the University of Illinois team, said the findings suggest that aerobic exercise has the potential to help roll back normal age-related declines in brain structure, though more evidence is needed.

Kramer said research demonstrates that aerobic exercise generates new neurons in the hippocampus, the area of the brain responsible for some aspects of memory. He said animal studies show a strong link between exercise and a sharper mind.

8220;Just a few weeks of exercise for mice and rats will improve their learning and memory in the tasks that are used to test these functions,8217;8217; Kramer said. 8220;We have no reason to believe that would be different for humans.8217;8217; Kramer said the team8217;s finding and those of others across the country are especially promising, because they offer people an easy, low-cost to path to better mental health. But while early data look promising, scientists say more research is needed to answer such questions as how much exercise is optimum and what kind of workout is best.

8220;What is still not quite determined is whether it8217;s physical fitness or physical activity,8217;8217; Hatfield said. 8220;Just moving may be the key, as opposed to being someone who can run the Marine Corps Marathon.8221;

Once that8217;s answered, another question will remain: Will the findings be enough to get people off the couch?