Putting one foot in front of the other may be a simple way for seniors who are already showing sign of cognitive impairment to slow down their mental decline, new research appears to suggest.
According to a study presented this week at the annual meeting of the Radiological Society of North America in Chicago, seniors with mild cognitive impairment who walked eight kilometres a week had a slower progression of mental decline over five years than those who did not.
The researchers, led by Cyrus Raji of the department of radiology at the University of Pittsburgh, reported similar results last month in the journal Neurology in a study that looked at healthy adults.
This research focused on 299 healthy adults and 127 cognitively impaired adults in Pittsburgh, including 44 with Alzheimer's and 83 with mild cognitive impairment (MCI). All patients were recruited from the Cardiovascular Health Study, a large prospective health study that began in the late 1980s.
Those with MCI typically have memory problems that go beyond typical age-related memory loss, yet are not yet as severe as those with Alzheimer's disease. About half of those with MCI progress to Alzheimer's disease.
The adults were given annual medical checks and questionnaires about their physical activity. Then, 10 years into the study, the patients underwent a 3-D brain scan to look for brain volume changes.
(Research has shown that when brain volume decreases, brain cells are dying which can lead to mental decline.)
Those who were cognitively normal at the time of the brain scan and who regularly exercised had a higher brain volume than the people who hadn't walked as much.
Those with cognitive impairment or Alzheimer's disease who also walked eight kilometres a week had better preservation of areas of the brain that are important in memory and learning, such as the hippocampus, the frontal lobes and the temporal lobes.
The patients with MCI were also given tests to track their cognitive decline over five years. The researchers found that those who walked at least eight kilometres a week had a slower progression of Alzheimer's disease and mild cognitive impairment, and a slower rate of cognitive decline over five years.
When the patients with cognitive impairment underwent tests to track their cognitive decline over five years, the researchers found that being physically active led to higher scores. The test scores went down only one point over five years in the individuals who walked five miles a week versus five points over five years for those who didn't.
Although the study was not designed to link cause and effect, Raji said he believed the findings showed that greater amounts of physical activity were associated with greater brain volume.
"Cognitively impaired people needed to walk at least 58 city blocks, or approximately five miles (eight kilometres), per week, to maintain brain volume and slow cognitive decline. The healthy adults needed to walk at least 72 city blocks, or six miles (9.6 kilometres), per week to maintain brain volume and significantly reduce their risk for cognitive decline," he said in a news release.
