Simple exercise, such as walking and resistance training, improved thinking and memory in older adults in several new studies that suggest physical activity offers a key strategy in slowing mental decline.
One trial found that walking may boost brain volume in the region for memory. Another showed that weight training helped the mental function of older women with mild cognitive impairment. The research was presented today at the Alzheimer's Association International Conference in Vancouver.
Current Alzheimer's drugs offer only temporary improvement in symptoms of the disease, which slowly destroys brain cells and robs patients of memory, thinking, concentration and function. Findings that even moderate amounts of exercise might benefit the brain may offer patients a simple, non- pharmaceutical tool to help to stave off mental decline, said Kirk Erickson, an author of one of the studies.
"People want to find a magic cure for Alzheimer's disease, but for memory function, a pair of sneakers might be just as important," Erickson, an assistant professor of psychology at the University of Pittsburgh in Pennsylvania, said in a July 13 telephone interview. "Physical activity appears to be an incredibly promising and effective approach and a non- pharmacological approach to improve brain function and hinder the progression of potential disease states like dementia and Alzheimer's disease. We have a lot more research to go before we can sell this as a prescription."
About 5.4 million Americans have Alzheimer's and, by 2050, that number is expected to grow to as many as 16 million, according to the Alzheimer's Association. The number of people worldwide with the condition is expected to swell to 115 million by 2050.
In the trial led by Erickson, researchers looked at 120 adults without dementia who engaged in moderate walking three times a week for 30 minutes to 45 minutes for a year or stretching and toning for the same periods of time. The researchers used magnetic resonance imaging, or MRI, to assess the areas of the brain responsible for memory that usually shrink with age.
They found a 2 percent growth in the area of the brain called the anterior hippocampus in those who exercised compared with those who engaged in stretching and toning.
"This is like essentially rolling back the clock by one to two years," Erickson said. More research is needed to determine if growth in that area continues with repeated exercise or levels off and what happens when someone stops exercising, he said.
A separate study led by researchers from the University of British Columbia in Vancouver found that twice-weekly weight lifting, or resistance training, may help alter the rate of mental decline in older women with mild cognitive impairment.
The trial followed 86 women ages 70 to 80 for six months who did resistance training, walking or balance and toning twice a week. Researchers found that the resistance-training group improved significantly on tests of mental functioning and memory over those in the balance and toning group. No memory benefit was seen among the walkers versus the balance and toning group.
Teresa Liu-Ambrose, the study's senior author and an assistant professor of physical therapy at the Vancouver Coastal Health Research Institute and the University of British Columbia, said strength training, which may be easier than aerobic activity such as walking for some older adults, requires people to think and learn new exercises, which may be why it worked better than walking in this study. Also, aerobic exercise may have to be done more frequently than twice a week to yield benefit in people already at risk for developing dementia, she said.
"Physical activity, whatever shape and form, is beneficial," she said in a July 13 telephone interview. What researchers now need to focus on is refining who benefits from which type of exercise program.
A step in that direction comes with the results from a third trial today, which Liu-Ambrose was also the principal investigator. That trial found that weight lifting is more effective than balance and toning in improving or maintaining selective attention and conflict resolution only among those with less cognitive impairment. The exercises yielded similar results in those who had more cognitive impairment.
A fourth study from Japan included 50 older adults with mild dementia who were assigned to exercise that included aerobic exercise, muscle strength training and postural balance retraining for 90 minutes a day twice a week for a year, or to an education group that attended three classes about health over 12 months. The researchers found that those in the exercise group performed better on memory tests than those in the education group.