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Frequent, brisk walks may curb dementia

According to a new study, exercise may bolster the brain function and thinking skills of people with dementia. The study’s findings suggest that walking a few times a 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 a person’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 brain function less efficient. In past brain-scan studies, people with a diagnosis of 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 shown that drugs used to artificially lower blood pressure too much, reduce the amount of oxygen delivered to the brain resulting in unnoticeable min-strokes which destroy brain cells. Our blood pressure normally rises as we age because extra pressure is required to send the blood-carrying oxygen to our brains. The norm for people over seventy is 135-140 over 80 to 90, not 120 over 80. So if our blood pressure is too low it can also be a cause of dementia.
Exercise can increase blood flow and improve cardiovascular health because we take in more oxygen and deliver more of it to our extremities, especially our brains. And some research suggests that frequent, brisk walks may improve memory and physical abilities in the early stages of Alzheimer’s disease. But very few past studies looked at how exercise affected brain function in people with vascular dementia.
In the new study which was published last April in the British Journal of Sports Medicine, researchers at the University of British Columbia 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 6 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. The 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 3 times a week. The walkers were asked to move briskly enough during workouts to raise their heart rates to about 65 per cent of their maximum capacity. Most of the walkers completed all of the sessions and even seemed to be enjoying their exercise by the end of the 6 months.
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 pressure now than the volunteers in the control group.
But more striking, their brains also were working differently. The walker’s 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 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.
Bottom line was that the walkers had more efficient brains and better thinking skills than did the control group.
Of course, this study was short term, lasting only six months, after which the volunteers were free to stop exercising—and, strangely enough, most did. The researchers plan to do another study to see how fast the non-walkers lose their cognitive ability.
Obviously anyone with memory or other cognitive problems should consult with a doctor before starting to exercise and should probably not exercise alone. After all, if you have hip or joint problems this may not be for you.
However the results are very encouraging. And now that June has arrived and all the greenery is about us, what can be healthier than a pleasant walk in the woods. [print_link]