In addition to all the other benefits of talking a walk, a
new study finds walking may slow cognitive decline in adults with mild
cognitive impairment (MCI) and Alzheimer's disease.
"We found that walking five miles per week protects brain
structure over 10 years in people with Alzheimer's and MCI, especially in areas
of the brain's key memory and learning centers," says Cyrus Raji, who is in the
combined M.D./Ph.D. program at University of Pittsburgh. "We also found that
these people had a slower decline in memory loss over five years."
The study was being presented at the annual meeting of the
Radiological Society of North America in Chicago.
The struggle to cope
Alzheimer's disease is an irreversible, progressive brain
disease that slowly destroys memory and cognitive skills, affecting between 2.4
million and 5.1 million Americans. Based on current population trends, that
number is expected to increase significantly over the next decade.
In cases of MCI, a person has cognitive or memory problems
exceeding typical age-related memory loss, but not yet as severe as those found
in Alzheimer's disease. About half of the people with MCI progress to Alzheimer's
disease.
"Because a cure for Alzheimer's is not yet a reality, we
hope to find ways of alleviating disease progression or symptoms in people who
already are cognitively impaired," adds Raji.
Testing patients
For the continuing study, the researchers analyzed the
relationship between physical activity and brain structure in 426 people,
including 299 healthy adults (mean age 78), and 127 cognitively impaired adults
(mean age 81), composed of 83 adults with MCI and 44 adults with Alzheimer's
dementia.
Researchers monitored how far each of the patients walked in
a week. After 10 years, all patients underwent 3-D MRI exams to identify
changes in brain volume, which is a vital sign for the brain. "When it
decreases," Raji points out, "that means brain cells are dying. But when it
remains higher, brain health is being maintained."
In addition, patients were given the mini-mental state exam (MMSE) to track cognitive decline over five years. Physical activity levels were correlated with MRI and MMSE results. The analysis adjusted for age, gender, body fat composition, head size, education, and other factors.
The case for walking
Across the board, 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, per week to maintain
brain volume and slow cognitive decline.
The healthy adults needed to walk at least 72 city blocks,
or six miles, per week to maintain brain volume and significantly reduce their
risk for cognitive decline.
Over five years, MMSE scores decreased by an average of five
points in cognitively impaired patients who did not engage in a sufficient
level of physical activity, compared with a decrease of only one point in
patients who met the physical activity requirement.
"Alzheimer's is a devastating illness, and unfortunately, walking is not a cure," notes Raji. "But walking can improve your brain's resistance to the disease and reduce memory loss over time."
