Moderate physical activity helps keep Alzheimer's disease at bay, according to a University of Maryland study.
Researchers said that physical activity protects brain health and avoids shrinking of the hippocampus, the region responsible for memory and spatial orientation. They said that the volume of the brain decreases along with age. But hippocampal degeneration in greater levels is observed in adults with enhanced genetic risk for Alzheimer's disease.
"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," Dr. J. Carson Smith, a kinesiology researcher in the School of Public Health, said in a press release.
For the study, the researchers tracked four groups of healthy older adults, aged 65-89, with normal cognitive abilities over an 18-month period. They measured the volume of their hippocampus using structural Magnetic Resonance Imaging or MRI at the beginning and end of the study.
Both the groups were associated with lower or higher Alzheimer's risk and physical activity levels.
The researchers found that participants with elevated genetic risk for Alzheimer's and who did not engage in any physical activity showed a 3 percent decrease in hippocampal volume. The remaining groups including physically active participants with high risk for Alzheimer's were able to maintain the volume of their hippocampus.
Participants were classified as high risk for Alzheimer's if their DNA test revealed the existence of genetic marker (polipoprotein E-epsilon 4 allele or APOE-e4 allele) on chromosome 19. The marker is known to increase the risk of developing the disease.
Dr. Kirk Erickson, an associate professor of psychology at the University of Pittsburgh, said that this is the first study to determine the positive impact of physical activity on the hippocampal volume in adults at genetic risk for Alzheimer's disease.
"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."
The finding is published in the journal Frontiers in Aging Neuroscience.
