Physical Activity Trumps Mental Activity, Study Suggests
By Salynn Boyles
WebMD Health News
Reviewed by Louise Chang, MD
Oct. 22, 2012 -- Staying mentally sharp as you age may have more to do with working out than working on crossword puzzles, new research suggests.
The brain typically shrinks in late adulthood, and this shrinkage is believed to play a role in age-related memory decline.
The new research is the latest to suggest that exercise is good for the brain as well as the body.
"It is pretty clear that exercise is one of the most potent things we can do to protect our brain as we age," says University of Pittsburgh exercise and aging researcher Kirk Erickson, PhD, who was not involved with the study.
Exercisers Had Larger Brains
The new research included about 700 people living in the United Kingdom who all had brain scans when they reached the age of 73.
Three years earlier, at age 70, the study participants were questioned about the leisure and physical activities they engaged in.
People in the study who reported being the most physically active tended to have larger brain volumes of gray and normal white matter, and physical activity was linked to less brain atrophy.
Regular exercise also appeared to protect against the formation of white matter lesions, which are linked to thinking and memory decline.
Non-physical leisure activities did not appear to protect the brain from shrinkage, suggesting that mental activity may be less important than regular exercise for preserving brain function into old age, the researchers say.
But researcher Alan J. Gow and colleagues from the University of Edinburgh add that more research is needed to prove this.
Mental Decline Not Inevitable
Erickson's latest research, presented this summer at the Alzheimer's Association International Conference in Vancouver, echoes Gow's research while suggesting that it's never too late to protect the brain through exercise.
Along with colleagues, he recruited 120 older inactive adults with no evidence of dementia for his study.
Half began a modest exercise routine that included walking at a moderate pace for 30 to 45 minutes, three times a week. The other half did stretching and toning exercises.
A year later, MRI brain scans showed that a key region of the brain involved with memory, known as the hippocampus, was slightly larger in the walking group, while it has shrunk slightly in the non-aerobic stretching group.
Erickson says the accumulating research is changing the thinking about how the brain ages.
"The old view is that as we get older our brains become less malleable and less able to change," he says. "The new view is that it remains plastic even very late in life. We were able to show positive change after just one year of moderate-intensity physical activity."
Orthopaedic surgeon Vonda Wright, MD, who studies aging athletes, says it is a myth that frailty and mental decline are inevitable in old age.
Wright directs a performance program for older athletes at the University of Pittsburgh and she is the author of the book Fitness After 40.
"It is never too late to harness our body's capacity to get stronger and more functional," she says. "There is no pill that can do what exercise does."
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