Moderate physical activity linked to big reductions in dementia risk

Staying active could be one of the simplest ways to lower your chances of developing dementia, even if you're older or frail. A recent study from researchers at the Johns Hopkins Bloomberg School of Public Health suggests that even a small amount of movement can make a significant difference.

The study, published in the journal JAMDA, found that engaging in at least 35 minutes of moderate to vigorous activity per week reduced dementia risk by 41% over an average follow-up period of four years.

As activity levels increased, so did the benefits. Those who exercised between 35 and 69 minutes weekly saw a 60% lower risk, while those who moved for 70 to 139 minutes experienced a 63% reduction. The highest activity group—140 minutes or more per week—had a 69% lower likelihood of developing dementia.

“Our findings suggest that increasing physical activity, even as little as five minutes per day, can reduce dementia risk in older adults,” said Amal Wanigatunga, PhD, MPH, the study’s lead author and an assistant professor at Johns Hopkins. He emphasized that any movement is better than none, particularly given the lack of a cure for dementia.

Dementia, most commonly caused by Alzheimer’s disease, affects about seven million people in the U.S., with roughly one-third of those aged 85 and older diagnosed with the condition. While aging is a major risk factor, growing evidence suggests that lifestyle changes—including managing blood sugar, blood pressure, and cholesterol—can help prevent or delay its onset.

To investigate the connection between movement and cognitive health, researchers analyzed data from nearly 90,000 British adults who participated in the UK Biobank project. These individuals, mostly in their 50s and older, wore wrist-worn accelerometers to track their activity levels for a week between 2013 and 2015. Their health was monitored for an average of 4.4 years, during which 735 participants were diagnosed with dementia.

By comparing the data, researchers observed a clear pattern: people who engaged in moderate to vigorous activity had a significantly lower risk of developing dementia compared to those who were completely inactive. The study also accounted for factors like age and existing medical conditions, strengthening the reliability of its findings.

A major takeaway from the study was that even frail or pre-frail individuals saw the same protective benefits from movement as healthier individuals. This challenges the idea that only those in peak physical condition can reap the rewards of exercise.

“This suggests that even frail or nearly frail older adults might be able to reduce their dementia risk through low-dose exercise,” Wanigatunga noted.

One concern the researchers addressed was whether the link between inactivity and dementia was due to undiagnosed cognitive decline leading to less movement rather than the other way around.

To test this, they excluded participants who were diagnosed with dementia within the first two years of follow-up. Even then, the results remained strong—more activity still meant a lower risk.

Currently, official guidelines from health agencies in the U.S. and the U.K. recommend at least 150 minutes of moderate-intensity exercise per week. However, for many older adults—especially those with limited mobility—this amount may seem daunting, discouraging any effort to be active at all. The study’s findings suggest that even much lower amounts of activity can still offer significant cognitive benefits.

The research underscores the importance of finding practical ways for older adults to stay active. Walking, gardening, light stretching, or even standing more frequently throughout the day could contribute to brain health.

While this study does not prove causation, it adds to growing evidence that exercise plays a vital role in cognitive health. Wanigatunga and his colleagues recommend that future research explore how smaller, more manageable amounts of movement might serve as a practical first step toward dementia prevention.

Exercise offers numerous health benefits for older adults, helping to improve physical, mental, and cognitive well-being. Here are some of the key advantages:

Encouraging regular exercise can significantly improve the quality of life for older adults, promoting longevity, independence, and overall well-being.

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