Exercise Might Help Protect the Aging Brain From Alzheimer's, Study Suggests

Photo: Leon Neal (Getty Images)

People at high risk for Alzheimer’s disease may be able to slow down the atrophy of their brains through regular aerobic exercise, a new study has found. The findings are a spot of good news for dealing with a disease that has proven seemingly impossible to treat.

Researchers at the University of Texas Southwestern Medical Center recruited 70 adults over the age of 55 for their trial. The volunteers all had documented mild cognitive decline, often a precursor to dementia, and were relatively sedentary. Half were randomly chosen to start aerobic exercise—the equivalent of a brisk half-hour workout four to five times a week—while the other half acted as sort of a control group and were asked to regularly stretch instead. Both groups carried out their new routines for a year.

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Indirect research continues to suggest that physical activity might be one of the few interventions that can prevent Alzheimer’s for some people. But the authors of the new study, published last month in the Journal of Alzheimer’s Disease, say theirs is the first trial of its kind to directly look at the impact of exercise on the brains and memory function of people at high risk of Alzheimer’s.

To be frank, the findings aren’t a home run. While both groups did report slightly better memory function a year later, those who worked out vigorously weren’t significantly better off than those who only stretched. That could mean that either kind of exercise can help people with mild cognitive decline stay healthier, but it isn’t necessarily what the authors were expecting to find.

However, when the authors looked more closely at the brains of their volunteers, they did find an intriguing pattern. Both groups on average experienced brain shrinkage and a build-up of amyloid plaque—the hardy, insoluble form of amyloid that’s thought to signify the progression of the disease (and may or may not help explain how Alzheimer’s destroys the brain). But those who had plaque to begin with and who worked out for a year did have less shrinkage of the hippocampus, a region of the brain crucial to our memory and one of the first areas that Alzheimer’s erodes.

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“It’s interesting that the brains of participants with amyloid responded more to the aerobic exercise than the others,” study author Rong Zhang, a neurology professor at UT Southwestern’s Institute for Exercise and Environmental Medicine, said in a statement released by the Journal of Alzheimer’s Disease. “Although the interventions didn’t stop the hippocampus from getting smaller, even slowing down the rate of atrophy through exercise could be an exciting revelation.”

Again, this isn’t a game changer, at least not for now. It’s a small pilot study, with the most promising results coming from an even smaller group of volunteers. And like so many potential interventions for Alzheimer’s that tested well initially, namely anti-amyloid drugs, it’s more than possible that larger trials will fail to find any major effect of exercise on people already on the path to dementia.

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That said, some studies have shown that active people are more likely to have healthier brains in their senior years. And given the many health benefits of exercise beyond the brain, especially for older people who aren’t active, it’s always worth it to be more physically fit. As to how fitness affects Alzheimer’s disease in particular, though, the jury is still out.

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About the author

Ed Cara

Science writer at Gizmodo and pug aficionado elsewhere