It’s not just your legs and heart that get a workout when you walk briskly; exercise affects your brain as well.
In a new study, researchers found that when older adults with mild memory loss followed an exercise program for a year, the blood flow to their brains increased.
The research was conducted by a team at UT Southwestern.
As many as one-fifth of people age 65 and older have some level of mild cognitive impairment (MCI) – slight changes to the brain that affect memory, decision-making, or reasoning skills.
In many cases, MCI progresses to dementia, including Alzheimer’s disease.
Scientists have previously shown that lower-than-usual levels of blood flow to the brain, and stiffer blood vessels leading to the brain, are associated with MCI and dementia.
Studies have also suggested that regular aerobic exercise may help improve cognition and memory in healthy older adults.
However, scientists have not established whether there is a direct link between exercise, stiffer blood vessels, and brain blood flow.
In the study, the team followed 70 men and women aged 55 to 80 who had been diagnosed with MCI. Participants underwent cognitive exams, fitness tests, and brain magnetic resonance imaging (MRI) scans.
Then they were assigned to either follow a moderate aerobic exercise program or a stretching program for one year.
The exercise program involved three to five exercise sessions a week, each with 30-40 minutes of moderate exercise such as a brisk walk.
Forty-eight study participants – 29 in the stretching group and 19 in the aerobic exercise group – completed the full year of training and returned for follow-up tests.
Among them, those who performed aerobic exercise showed decreased stiffness of blood vessels in their neck and increased overall blood flow to the brain.
The more their oxygen consumption (one marker of aerobic fitness) increased, the greater the changes to the blood vessel stiffness and brain blood flow.
Changes in these measurements were not found among people who followed the stretching program.
While the study didn’t find any significant changes in memory or other cognitive function, the researchers say that may be because of the small size or short length of the trial.
Changes to blood flow could precede changes to cognition, they say. They’re already carrying out a larger two-year study that further tests the link between exercise and cognitive decline.
The study is published in the Journal of Alzheimer’s Disease. One author of the study is Rong Zhang, Ph.D., a professor of neurology.
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