By GRETCHEN REYNOLDS MAY 24, 2017
Exercise may bolster the brain function and thinking skills
of people with dementia, according to a new report. The study’s findings
suggest that walking a few times per week might alter the trajectory of the
disease and improve the physical well-being of people who develop a common form
of age-related memory loss that otherwise has few treatments.
The study looked at vascular cognitive impairment, the
second most frequent form of dementia worldwide, after the better-known Alzheimer’s
disease. The condition arises when someone’s blood vessels become damaged and
blood no longer flows well to the brain. It is often associated with high blood
pressure and heart disease.
One of the particular hallmarks of vascular dementia in its
early stages, researchers have found, is that it tends to make the brain
function less efficiently. In past brain-scan studies, people with a diagnosis
of vascular cognitive impairment generally showed more neural activity in parts
of their brains that are involved with memory, decision-making and attention
than did people without the disease, indicating that their brains had to work
harder during normal thinking than healthier brains did.
But while a great deal of research attention has been
devoted to Alzheimer’s disease, less has been known about the progression of
and potential curbs on vascular dementia. Some research has indicated that
reducing blood pressure lessens the symptoms of the disease.
Exercise can likewise improve blood pressure and
cardiovascular health. And some research suggests that frequent, brisk walks
may improve memory and physical abilities in those in the early stages of
Alzheimer’s disease. But, rather surprisingly, few past studies had examined
whether exercise might also improve brain function in people with vascular
dementia.
So for the new study, which was published in April in The
British Journal of Sports Medicine, researchers at the University of British
Columbia in Canada and other institutions decided to look into the effects of
walking on this type of dementia.
They began by recruiting 38 older people in British Columbia
who had been given diagnoses of a mild, early form of vascular cognitive
impairment. None currently exercised. All agreed to visit the university’s lab
frequently for six months.
On the participants’ first lab visit, the scientists
measured their general health and also memory and thinking skills.
They then scanned each volunteer’s brain while he or she
concentrated on a computerized test of attention and decision-making skills
that involved rapidly clicking keys to indicate the direction that an arrow
should point. This scan was designed to reveal neural activity and how hard
different parts of the brain were working during the task.
Finally, the scientists randomly assigned their volunteers
to start either walking or, as a control group, to visit the lab for weekly
education sessions about nutrition and healthy living.
The walking program was simple, consisting of supervised
one-hour sessions at the lab three times a week. The walkers were asked to move
briskly enough during workouts to raise their heart rates to about 65 percent
of their maximum capacity.
“We wanted to have some intensity” in the exercise, says
Teresa Liu-Ambrose, the director of the Aging, Mobility and Cognitive
Neuroscience Lab at the University of British Columbia and the lead author.
Most of the walkers completed all of the sessions and “seemed to be enjoying
the exercise” by the end of the six months, she says.
At that point, the volunteers in both groups repeated the
physical and cognitive tests from six months earlier, as well as the brain
scan. The results showed that the two groups had drifted apart, in terms of the
functions of their bodies and brains. Most obviously, the walkers generally had
lower blood pressures now than the volunteers in the control group.
But more striking, their brains also were working
differently. The walkers’ brains showed less activation in portions of the
brain required for attention and rapid decision-making than did the brains of
those in the control group.
The differences were subtle, Dr. Liu-Ambrose says, but they
correlated neatly with improvements on the cognitive tests. The less someone’s
brain had to work to maintain attention and make quick decisions, the better
that person typically performed on the tests of general thinking ability.
In essence, the walkers had more efficient brains and better
thinking skills now than the control group did, she says.
Of course, this study was short term, lasting only six
months, after which the volunteers were free to stop exercising — and most did.
Dr. Liu-Ambrose and her colleagues hope in the future to study whether and how
rapidly the brains and bodies of exercisers lose any gains if they become
sedentary again. They also want to look into different “doses” of exercise and
whether shorter or easier workouts would have an effect on brain function in
people with vascular dementia.
Obviously, anyone with memory or other cognitive problems
should consult with a doctor before starting to exercise and should probably
not exercise alone, Dr. Liu-Ambrose says.
But even with so many questions remaining, the results of
this study are encouraging, she says. They show that in the early states of
vascular dementia, “something as simple and accessible as walking may make a
meaningful difference” in how well the brain works.
Reprinted from: https://www.nytimes.com/2017/05/24/well/move/a-1-hour-walk-3-times-a-week-has-benefits-for-dementia.html?_r=1
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