Walking linked to improved brain function
May 16, 2017 By Shereen Lehman
A moderate-intensity walking
regimen may reduce symptoms of mild cognitive impairment that are linked to
poor blood vessel health in the brain, a small study suggests.
Participants with vascular cognitive impairment, sometimes
called vascular dementia, who walked 3 hours per week for 6 months had improved
reaction times and other signs of improved brain function, the Canadian team
reports in British Journal of Sports Medicine.
Vascular cognitive impairment, or VCI, refers to mildly impaired
thinking or more advanced dementia that’s due to the same kinds of blood vessel
damage seen with heart disease elsewhere in the body. It is the second most
common cause of dementia after Alzheimer’s disease. “It is well established that regular aerobic
exercise improves cardiovascular health and cerebrovascular health,” the
study’s senior author Teresa Liu-Ambrose told Reuters Health in an email.
“More specifically, it reduces one’s risk of developing chronic
conditions such as high blood pressure, diabetes (type II), and high
cholesterol. These chronic conditions have a negative impact on the brain -
likely through compromised blood flow to the brain,” said Liu-Ambrose, a researcher
with the Aging, Mobility, and Cognitive Neuroscience Lab at the University of
British Columbia in Vancouver. The brain
is a highly metabolic organ and to keep it healthy, it requires good blood flow
to deliver the necessary nutrients and oxygen to its tissues, she added.
“It is worth noting that in our study, reduced blood pressure
(secondary to exercise) was associated with improved cognitive function,”
Liu-Ambrose said. Aerobic exercise may
also benefit the brain by increasing growth factors, which are substances made
by the body that promote cell growth, differentiation and survival, she said. Liu-Ambrose and colleagues randomly assigned
38 older adults with mild VCI to one of two groups. One group followed an
aerobic training program consisting of three one-hour walking classes each week
for six weeks, while the other group continued with their usual care. In
addition, both groups were given information about vascular cognitive
impairment and tips for eating a healthier diet.
Before the exercise program began and at the end of six weeks,
all the participants also had functional MRI brain scans and other tests that
measured neural activity and cognitive ability.
People in the aerobic training group had significant improvements in
their reaction times on the cognitive tests, and showed changes in their brain
activity that made them resemble healthy brains more. The comparison group
showed no changes.
Overall, exercise appears to be a promising strategy for
promoting cognitive health in older adults, Liu-Ambrose said.
“While more research is needed to better understand how it
brings about its benefits and what factors may impact the degree of benefit
observed, there is minimal negative consequence of exercising,” she said.
Liu-Ambrose said she doesn’t know if exercise can actually
prevent VCI because there have been no studies to determine that. “However,
population based studies do suggest that physical activity does reduce the risk
of developing VCI. Moreover, as mentioned earlier, aerobic exercise is very
effective in reducing vascular risk factors associated with VCI, such as high
blood pressure.”
The study was small, and because participants had to be able to
walk for up to an hour, it’s possible they were physically healthier than
average, the authors note. The socializing involved in the walking classes
might have also had some effect, they add.
“Given the small sample size, one needs to be cautious about
interpreting the results of this pilot study. However, it is encouraging to see
that the six-month aerobic exercise program improved certain aspects of
cognition and showed changes on functional brain imaging,” said Dr. Joe
Verghese, director of the Montefiore Einstein Center for the Aging Brain at
Montefiore Medical Center in New York.
“The effect of exercise in this, and other studies seems to be
on improving executive functions, which are required for planning, thinking and
judgment,” Verghese, who wasn’t involved in the study, said by email.
“The findings, if confirmed in larger studies, may have implications
in advising exercise in older patients with vascular risk factors for brain
protection,” Verghese said.
SOURCE: http://bit.ly/2pXErCo British Journal of Sports
Medicine, online April 21, 2017.
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