Exercise Keeps Your Brain from Shrinking

Simply gardening, dancing or golfing helps fend off dementia, researchers say

Image: Science Photo Library/Getty Images

OOlder people who get regular physical activity, even through relatively light pursuits like gardening or golf, have bigger brains compared to inactive older people, a new study suggests. The finding adds to a mountain of research showing that physical activity helps prevent brain shrinkage and slow the effects of brain aging that lead to cognitive decline and dementia.

In the new research, brain scans of 1,557 older people, average age 75, revealed that the most-active third of them had a brain volume 1.4% greater than the least-active third, a difference equivalent to being four years younger, the researchers say.

People in the most-active group reported getting either seven hours of low-intensity physical activity weekly (things like gardening, dancing, golf, or bowling), or four hours of moderate activity (such as tennis, swimming, or hiking), or two hours of high-intensity activity (serious workouts such like jogging or handball).

“These results are exciting, as they suggest that people may potentially prevent brain shrinking and the effects of aging on the brain simply by becoming more active,” says the study’s lead author, Yian Gu, PhD, an assistant professor of neurological sciences at Columbia University.

The preliminary findings, not yet published, will be presented at the American Academy of Neurology’s annual meeting in Toronto this spring.

The study was not designed to determine if these more active people are at lower risk for dementia. But a separate study by Gu and her colleagues, published in December in the Alzheimer’s & Dementia Journal, found physical activity “associated with lower risk of developing Alzheimer’s disease,” she tells Elemental.

Other studies find dancing indeed bulks up that hippocampus, and gardening boosts levels of growth factors known to be good for the brain.

Fit body, fit mind

The devastating effects on the brain from Alzheimer’s, the most common form of dementia, develop across many years. While there are some medications that can help curb symptoms, there is no cure and no known medical interventions to slow its progress.

Meanwhile, research has shown that healthier lifestyles can lower the risk of developing dementia, and several studies have shown that moderate physical activity, including brisk walking, improves brain power.

One study last year found that people who exercised moderately for six months did far better than sedentary people on tests measuring the ability to pay attention, organize tasks, and achieve goals. The effects were found for all age groups. “The people who exercised were testing as if they were about 10 years younger at age 40 and about 20 years younger at age 60,” said study leader Yaakov Stern, PhD, a professor of neuropsychology at Columbia University.

Conversely, poor cardiovascular health at age 50 raises the risk of dementia later in life, another study last year revealed.

A broad analysis of several studies, done in 2017, found aerobic exercise prevents shrinkage of the hippocampus, a part of the brain key to learning and memory. Further research published in 2018 and 2019 laid to rest the long-standing controversy over whether older people can grow new brain cells. They can, and the new cells can increase volume in the hippocampus.

Other studies find dancing indeed bulks up that hippocampus, and gardening boosts levels of growth factors known to be good for the brain.

Visible effects

The benefits of exercise can be starkly visible in the brain. A recent study took brain scans of people who did moderate physical activity on a treadmill three days a week and compared them to a sedentary control group. All the people had risk factors for Alzheimer’s but were not yet showing signs of the disease.

Photo: Glucose metabolism is shown in a sedentary person (left) and in someone after a 26-week program of moderate exercise (right). Images: Brain Plasticity journal

After six months, people who had exercised had increased levels of brain glucose metabolism in a part of the brain linked to Alzheimer’s — a good sign of healthy neurons. And they did better on tests of cognition for things like planning, focusing attention, and juggling multiple tasks.

Finally, a study earlier this year in the journal Mayo Clinic Proceedings directly supports the new work by Gu and her colleagues. Researchers used brain scans of more than 2,000 people, ages 21 to 84, to show that exercise results in a slowing of aging-related reduction in total brain volume and volume of gray matter, which they say is also associated with cognitive decline.

“There is good evidence for the value of exercise in midlife, but it is encouraging that there can be positive effects on the brain in later life as well,” says Dr. Ronald Petersen, a Mayo Clinic neurologist who co-wrote an editorial on the findings.

Explainer of things, independent health and science journalist, author, former editor-in-chief of LiveScience and Space dot com.

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