Endurance Exercise May Be a Speed Bump That Slows Down Alzheimer’s

It’s never too late to start healthy habits that can reduce your risk.

By Elizabeth Millard

Oct 4, 2019

 

Heide BenserGetty Images

• Endurance exercise can reduce the progression of atrophy in a part of the brain associated with memory among people at risk of Alzheimer’s disease, a new study found.
• Exercise can improve blood vessel health and boost the production of compounds that support developing brain neurons, experts believe.

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Currently, there is no cure for Alzheimer’s disease, and previous research has discovered that the rate of progression and changes in brain atrophy—or the loss of nerve cells called neurons in your brain—often varies by individual, making the condition even tougher to predict and treat.

But a new study published in the Journal of Alzheimer’s Disease joins a growing tide of research about one possible speed bump for dementia and Alzheimer’s: regular exercise.

Researchers at UT Southwestern Medical Center compared cognitive function and brain volume in 70 sedentary, older adults with memory issues and mild cognitive impairment. They separated them into two groups, one doing aerobic exercise and the other concentrating on stretching.

The dose of aerobic training was based on each individual’s fitness level, assessed with VO2 testing, But no matter what their starting point, every participant in that group progressively increased the frequency and intensity of their exercise sessions over time, starting with three times per week for about a half hour at 75 to 85 percent of max heart rate.

By week 26, they were doing four to five sessions per week for about 40 minutes per time, at 85 to 90 percent of max heart rate for the workout.

The stretching group participants stayed at below 50 percent of max heart rate and focused on full-body stretches, with resistance bands introduced about halfway through the program.

At the end of a year, both groups showed evidence of slightly improved neuropsychological scores, and scored about the same on cognitive tests. Memory and executive function—which includes things like reasoning and problem-solving skills—also improved for all participants.

But when the researchers looked at how the buildup changed of amyloid—a type of plaque that’s considered a hallmark of Alzheimer’s and dementia because it destroys neurons in the brain—they saw some important differences:

Those in the exercise group who had amyloid buildup at the start of the study experienced slightly less volume reduction in their hippocampus—the part of the brain involved in memory—compared to those in the stretching group.

This is a big deal because previous research has shown that people who have more amyloid beta also tend to experience more shrinkage in that part of the brain.

So if exercise can keep the amyloid in check, then that could mean dementia could progress at a slower rate. The reason why aerobic exercise has this effect isn’t clear yet, according to lead author Ron Zhang, Ph.D., professor of neurology and neurotherapeutics at UT Southwestern. But, he told Bicycling, it may have to do with how exercise enhances brain neurotrophic factors—molecules that support developing neurons—and blood vessel function, which could both reduce the harmful effects of amyloid on your brain cells.

He added that further studies need to be done, especially in large, randomized, controlled trials, to determine how much exercise is needed for the best effect, especially since people can respond to exercise differently.

“But, for now, it would be safe to say that engaging in moderate to vigorous physical activity not only benefits your heart, but also your brain,” said Zhang.