Exercise Helps Brain Health

By Jane Farrell

Add one more to the already long list of exercise benefits: A study of older adults at increased risk for Alzheimer's disease shows that moderate physical activity may protect brain health.

Everyone loses some brain volume with age, but people with a genetic risk for Alzheimer’s usually show greater weakening overtime in the area of the brain known as the hippocampus. The hippocampus is responsible for memory and spatial orientation.

"The good news is that being physically active may offer protection from the neurodegeneration associated with genetic risk for Alzheimer's disease," said J. Carson Smith, a kinesiology researcher in the University of Maryland School of Public Health who conducted the study. “We found that physical activity has the potential to preserve the volume of the hippocampus in those with increased risk for Alzheimer's disease, which means we can possibly delay cognitive decline and the onset of dementia symptoms in these individuals. Physical activity interventions may be especially potent and important for this group."

The findings were published in the journal Frontiers in Aging Neuroscience.

In the study, Smith and colleagues, including Dr. Stephen Rao from the Cleveland Clinic, tracked four groups of healthy older adults ages 65-89, who had normal cognitive abilities, over an 18-month period. Using magnetic resonance imaging , they measured the patients’ hippocampus volume at the beginning and end of the study. The groups were classified both for low or high Alzheimer's risk (based on the absence or presence of the apolipoprotein E epsilon 4 allele) and for low or high physical activity levels.

Of all four groups studied, only those at high genetic risk for Alzheimer's who did not exercise experienced a decrease in hippocampal volume (3 percent) over the 18-month period. All other groups, including those at high risk for Alzheimer's but who were physically active, maintained the volume of  their hippocampus.

"This is the first study to look at how physical activity may impact the loss of hippocampal volume in people at genetic risk for Alzheimer's disease," said Dr. Kirk Erickson, an associate professor of psychology at the University of Pittsburgh. "There are no other treatments shown to preserve hippocampal volume in those that may develop Alzheimer's disease. This study has tremendous implications for how we may intervene, prior to the development of any dementia symptoms, in older adults who are at increased genetic risk for Alzheimer's disease."

Previous research has shown that walking exercise for people with mild cognitive dementia improved cognitive function.

shown that a walking exercise intervention for patients with mild cognitive decline improved cognitive function by improving the efficiency of brain activity associated with memory. He is planning to conduct a prescribed exercise intervention in a population of healthy older adults with genetic and other risk factors for Alzheimer's disease and to measure the impact on hippocampal volume and brain function.