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Researchers followed more than 2,500 people over 17 years—let’s break down what they found.

Reviewed by Dietitian Jane Leverich, M.S., RDN

Key Points

• Memory decline may reduce physical activity, especially light activities like walking or household chores.
• Older adults with worsening memory spend more time sedentary, highlighting brain-health’s role in movement.
• Supporting physical activity in aging adults may require structured plans to ease cognitive demands.

Maintaining independence and well-being as we age requires a delicate balance of physical capability and mental sharpness. The good news is that staying physically active is a powerful way to protect the brain against cognitive decline—so your workouts could be helping you strengthen your body and your mind.

Health professionals routinely recommend walking, swimming and other movements as low-impact ways to keep moving as you get older, and those exercises have been connected to better brain health—but now scientists are now exploring the reverse side of this equation, too. Researchers want to understand if a decline in memory and thinking actually causes older adults to become less physically active over time. To do this, scientists recently evaluated information from over 2,000 adults, and the results were published in JAMA Network Opena journal of the American Medical Association.

How Was the Study Conducted?

To understand how brain health impacts physical movement, researchers examined information from 2,529 adults aged 50 and older living in the United Kingdom.

The study took a long-term approach, tracking the cognitive trajectories of these participants over a 17-year period. During this time, researchers regularly measured memory and verbal fluency. Memory was assessed through immediate and delayed word recall tasks, while fluency was tested by asking participants to name as many animals as possible within a set time. By looking at these tests over nearly two decades, the researchers could plot an individual trajectory for each person, showing whether their cognitive function remained stable, improved slightly, or declined.

After establishing these 17-year cognitive trajectories, the researchers needed an accurate way to measure how much the participants moved. Participants wore wrist accelerometers, similar to modern fitness trackers, 24 hours a day for eight consecutive days. These devices recorded the exact amount of time participants spent in moderate-to-vigorous physical activity, light physical activity, sedentary behavior and sleep.

What Did the Study Find?

The data revealed a clear association between long-term cognitive health and subsequent physical activity levels. Specifically, participants who experienced a less favorable memory trajectory, meaning their memory declined more noticeably over the 17 years, spent less time being physically active later in life.

When looking at the numbers, individuals with steeper memory decline engaged in about 1.6 fewer hours of light physical activity per week compared to those with stable or improving memory trajectories. Light physical activity includes everyday movements like casual walking, light household chores and preparing meals.

Age played a major role in these findings. For participants over the age of 70, the gap in physical activity became even more pronounced. In this older group, those with less favorable memory trajectories logged 2.3 fewer hours of light physical activity per week.

Alongside the drop in light activity, the researchers noted an increase in sedentary behavior. Those whose memory declined faster spent more of their day sitting or lying down while awake. Interestingly, the study found that changes in memory had a much stronger association with movement patterns than changes in verbal fluency. Additionally, the differences in moderate-to-vigorous activity and sleep time were minor across the different cognitive trajectories.

Limitations

While the study provides valuable insights, it does have a few limitations to consider. Because the group was 95% white, we should be cautious about assuming these exact patterns apply universally to all populations. The researchers also noted the possibility of residual confounding. Even though they adjusted the data for many health and lifestyle factors, like financial status, education, smoking and chronic illnesses, other unaccounted variables could still influence the results.

Finally, relying on wrist-worn accelerometers presents some technical challenges. While they are far more accurate than human memory for tracking movement, these devices can sometimes struggle to distinguish between sedentary behavior (like sitting quietly on the couch) and actual sleep time. Because they measure movement at the wrist, the data on exact sleep duration versus simple inactivity may contain slight misclassifications.

How Does This Apply to Real Life?

These findings offer a practical perspective on how we view aging, health and independence. When an older adult begins to slow down, sit more or drop their usual light activities, we may assume the cause is purely physical. We might blame aching joints, muscle fatigue or a general loss of physical stamina.

This research suggests we need to look closer. A reduction in everyday movement might actually be an early indicator of cognitive changes. The brain needs a certain amount of processing power and organizational capacity to plan, initiate and sustain physical tasks. If memory and cognitive resources begin to fade, the natural drive and ability to stay active can fade with them.

For families and caregivers, this means that supporting an older adult’s physical activity might require more than just encouraging them to move. We may need to provide structured support, gentle reminders and organized activities that remove the cognitive burden of planning out physical tasks. By recognizing that brain health and physical activity are deeply connected, we can better support the holistic well-being of aging adults.

Our Expert Take

We know that exercise benefits the brain, but this research published in JAMA Network Open clearly illustrates that a healthy brain is also necessary to maintain an active life. The study design is particularly strong. Tracking cognitive changes over 17 years provides a highly reliable picture of brain health, avoiding the pitfalls of single point-in-time memory tests.

While the absolute differences in daily movement might seem modest, shifting by a few hours a week, even slight increases in light physical activity may improve longevity and health outcomes in older adults. Protecting memory and thinking skills is a critical step in preserving physical independence as we age.