Walking five miles per week may protect the brain and slow cognitive decline in people with mild cognitive impairment (MCI) and Alzheimer’s disease, said researchers at a conference of medical imaging professionals in Chicago on Sunday; they also found that walking six miles a week did the same for healthy people.
Dr Cyrus Raji, from the Department of Radiology at the University of Pittsburgh in Pennsylvania, presented the findings of a study where he and his colleagues analyzed changes in brain volume among adults with varying degrees of congnitive impairment, including some with Alzheimer’s, and also healthy adults, whose weekly physical activity had been monitored in a cardiovascular study over the previous 10 years.
Speaking at the 96th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA), being held this week in Chicago, Raji said:
“We found that walking five miles per week protects the brain structure over 10 years in people with Alzheimer’s and MCI [mild cognitive impairment], especially in areas of the brain’s key memory and learning centers.”
“We also found that these people had a slower decline in memory loss over five years,” he added.
MCI, short for Mild Cognitive Impairment, is where a person has more problems with memory and thinking skills than is typical for their age, but it is not as severe as that found in Alzheimer’s disease. About 50 per cent of people diagnosed with MCI progress to Alzheimer’s disease.
The numbers of Americans with MCI and Alzheimer’s is set to increase significantly over the next decade, based on current population trends.
There is no cure for Alzheimer’s, which is why researchers like Raji and colleagues are keen to find ways to alleviate the symptoms and slow the progression of the disease in people whose thinking and memory are already showing signs of decline.
Raji and colleagues recruited participants from the Cardiovascular Health Study, which is still ongoing, and has been collecting data for 20 years, and analyzed the relationship between their physical activity and brain structure.
Their study involved 426 participants in all, comprising 127 cognitively impaired adults of average age 81 years, and 299 healthy adults of average age 78. Of the cognitively impaired participants, 83 had MCI and 44 had Alzheimer’s dementia.
The study data allowed the researchers to measure how far participants walked in a week. Then 10 years later they performed 3D MRI scans of their brains to look for changes in brain volume.
Raji explained that:
“Volume is a vital sign for the brain.”
“When it decreases, that means brain cells are dying. But when it remains higher, brain health is being maintained,” he said.
In addition, the participants completed the mini-mental state exam (MMSE) which allowed the researchers to track cognitive decline over five years.
Raji and colleagues then correlated physical activity levels with MRI and MMSE resuts and adjusted the results to take out any influence due to differences in age, gender, body mass index (BMI), head size, education and other potential confounders such as “white matter hyperintensities”, believed to be a type of brain cell damage linked to vascular risk factors of dementia.
The main result showed that across the board, the more exercise participants took, the greater their brain volume.
In their session abstract, the researchers noted that “greater physical activity was linked to greater volumes of “frontal, occipital, temporal, entorhinal, and hippocampal regions 9 years later”.
For participants with cognitive impairment, walking at least 58 city blocks, or 5 miles, per week, was linked to preservation of brain volume and slower cognitive decline, said Raji.
For healthy participants, walking at least 72 city blocks, or six miles, per week was enough to maintain brain volume and significantly reduce risk of cognitive decline, he added.
Walking more than this threshold level did not appear to preserve any more brain volume, noted the researchers.
The results showed that over five years, for the cognitively impaired participants who did not attain the threshold level of activity, the scores on the MMSE cognitive test went down by five points on average, compared to only one point on average for those who did meet the physical activity requirement.
“Alzheimer’s is a devastating illness, and unfortunately, walking is not a cure.”
But it can help your brain resist the disease and slow down memory loss, he added.
The National Institute on Aging estimates that between 2.4 and 5.1 million American’s have Alzheimer’s disease, a devastating, irreversible and progressive brain disease that gradually destroys memory and thinking; in advanced stage, people lose the ability to carry on a conversation and respond to their environment.
Alzheimer’s is the sixth leading cause of death in the United States, where it accounts for 50 to 70 per cent of dementia cases. Although the majority of people who get the disease are aged 65 and over, around 1 in 20 cases are early onset, affecting people in their 40s and 50s.
“Physical Activity and Gray Matter Volume in Late Adulthood: The Cardiovascular Health Cognition Study.”
Cyrus Raji, Kirk Ericson, Oscar Lopez, James Becker, Caterina Rosano, Anne Newman, H. Michael Gach, Paul Thompson, April Ho, Lewis Kuller
Presented 28 November 2010, at RDNA 2010, 96th Scientific Assembly and Annual Meeting of the Radiological Society of North America, in Chicago.
Neuroradiology (Ischemia and Infarction) session, Abstract code: SSA17-01
Additional sources: RSNA News Release, Alzheimer’s Association, University of California Science Today (White Matter Matters, 2007-10-23).
Written by: Catharine Paddock, PhD