Physically active life good for the body and brain
Fri Aug 11, 2006 1:44 PM ET
By Megan Rauscher
NEW YORK (Reuters Health) - Exercise keeps the body, and mind, in tiptop shape, according to a review of published studies on the topic. Taken together, the data suggest that exercise and physical activity may slow age-related declines in cognitive function, the reviewers conclude.
Moreover, fitness training may improve some mental processes even more than moderate activity.
"Although we clearly still have much to learn about the relationship between physical activity and cognition, what we currently know suggests that physical activity can help keep us both healthy and mentally fit," Dr. Arthur F. Kramer told Reuters Health.
Kramer, from the Beckman Institute at the University of Illinois in Urbana, presented his team's work this week at the annual gathering of the American Psychological Association. The research is scheduled for publication in an upcoming issue of the Journal of Applied Physiology.
In an effort to resolve the "varied opinions" on the impact of exercise on cognitive functioning, Kramer and colleagues conducted an "up-to-date" review of the scientific literature on the subject.
They found that many of the studies suggest "significant, and sometimes substantial" links between physical activity and later cognitive function and dementia. There is evidence that this relationship can span several decades.
In one study, for example, participating twice weekly in leisure time physical activity in middle age was associated with a reduced risk of dementia later in life.
However, "given the observational nature" of most of the studies on exercise and the brain, a "cause and effect" relationship cannot be established, Kramer and colleagues point out.
"Fortunately, there have been an increasing number of randomized intervention studies which have examined the relationship between fitness training and cognition and dementia," they note.
Some of these studies have shown significant improvements in mental performance and delayed dementia with fitness training, whereas others have not.
Pooled data from 18 intervention studies suggests a "moderate" positive influence of fitness training, particularly on "executive control" functions such as planning, scheduling, working memory and multi-tasking -- many of the processes that often show substantial decline with age.
Exercise is not only beneficial for healthy people but also for those already showing signs of dementia and related cognitive impairments, the team reports.
The medical research literature also contains evidence that "even relatively short exercise interventions can begin to restore some of the losses in brain volume associated with aging," they add.