Jan. 29, 2003 -- Exercising regularly as you get older may not only keep your body in shape, but your brain as well. Scientists have discovered new evidence that aerobic exercise can help protect brain tissue from age-related damage and mental decline.
Although previous research has already shown that physical fitness can improve brain function and health in older adults, a new study provides visible proof of the benefits of exercise in the brain scans of older adults.
The study, published in the February issue of the Journal of Gerontology: Medical Sciences, found significant differences in the areas of the brain most affected by aging, which varied according to the fitness levels of the men and women studied.
According to researchers, the brain loses an average of 15% to 25% of its tissue between the ages of 30 and 90, and most of these losses are in the areas associated with memory, learning, and other thinking-related processes.
In the study, researchers used magnetic resonance imaging (MRI) to analyze three-dimensional brain scans of 55 well educated adults aged 55 to 79 who ranged in fitness from sedentary to competition-ready athletes . Fitness levels were assessed with one-mile walking and treadmill tests.
"Interestingly, we found that fitness per se didn't have any influence on brain density," says researcher Arthur Kramer, PhD, of the Beekman Institute at the University of Illinois at Urbana-Champaign and colleagues, in a news release. "It is fitness as it interacts with age that has the positive effects. Older adults show a real decline in brain density in white and gray areas, but fitness actually slows that decline."
Researchers say the area of the brain called gray matter consists of the tissues involved in learning and memory, while the white matter contains nerve fibers that transmit signals throughout the brain. In comparing the brain scans of the physically fit with those of sedentary adults, they found the most distinct differences were in these two types of brain tissue -- those associated with memory and learning.
It wasn't that fitter people had better brain densities; it was that exercise decreased the amount of brain-tissue loss associated with aging.
"This, to our knowledge, is the first human data providing a potential anatomical account of the cognitive effects that we and others have found over the years," says Kramer.
Researchers say those results suggest that the benefits of aerobic exercise extend well beyond cardiovascular health markers and can effect brain health as well, but more research is needed to precisely understand those effects.