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Sept. 2, 2008 -- Older adults who take a brisk stroll just three times a week could boost their brainpower and reduce the risk of memory-robbing illnesses such as Alzheimer's disease.
Research published in this week's issue of The Journal of the American Medical Association is believed to be the first to show that home-based exercise improves cognitive function in adults with mild cognitive impairment (MCI), a stage between normal aging and dementia. MCI is marked by mild forgetfulness, language difficulties, and other cognitive problems that are noticeable but do not interfere with everyday tasks.
Nicola T. Lautenschlager, MD, of the University of Melbourne, Australia, and colleagues wanted to see if physical activity would reduce the rate of cognitive decline among older adults at risk for dementia. Their study involved 138 adults aged 50 and older with self-reported memory problems but who did not meet criteria for dementia. The average age was 69 years old.
Researchers randomly assigned study participants to education and usual care or a 24-week home-based exercise program. The team encouraged those in the exercise group to get at least 150 minutes of moderate intensity activity each week, broken down into three, 50-minute sessions. Walking was the most frequently recommended type of activity.
Those assigned to the activity program exercised 142 more minutes each week, or 20 more minutes per day, than those in the usual care group. "At 6 months, participants in the physical activity group were walking about 9,000 steps a week more than the usual care group," the team writes in the journal article.
Those in the exercise group scored higher on cognitive tests and had better delayed recall. For example, they could more accurately remember a list of words after a certain amount of time had passed than those in the other group.
Researchers also noted lower Clinical Dementia Rating scores among those who were more physically active.
Lautenschlager says the benefits could be seen after 6 months and that they lasted for at least a year after the program's end.
"Unlike medication, which was found to have no significant effect on mild cognitive impairment at 36 months, physical activity has the advantage of health benefits that are not confined to cognitive function alone, as suggested by findings on depression, quality of life, falls, cardiovascular function, and disability," the authors say in a news release.
Alzheimer's disease is an incurable brain disease that robs a person of the mental abilities that affect memory and learning. It is the sixth-leading cause of death in the United States. According to the Alzheimer's Association, about 5 million people in the United States live with the condition. However, the number is expected to substantially increase in the coming decades as America's baby boomers reach their golden years. Study authors say delaying the onset of illness by one year would dramatically reduce the number of cases seen around the world.