Study: Declining Physical Activity in Older Adults May Signal Cognitive Changes

A study published in JAMA Network Open has found an association between memory decline and reduced physical activity in adults aged 50 and older. The research, which followed 2,529 adults in England over 17 years, indicates that participants with greater memory decline spent about 14 fewer minutes per day in light physical activity and 12 more minutes sedentary compared to those with more favorable memory trajectories. Over a week, this difference accumulates to approximately 1.6 additional hours of light activity for those with slower cognitive decline.

The findings suggest that cognitive decline may partly lead to reduced physical activity rather than the reverse, according to study author Mikaela Bloomberg, PhD, a Senior Research Fellow at University College London. Bloomberg told Medical News Today that the relationship between brain health and movement is likely bidirectional, cautioning that observational links between exercise and dementia risk should be interpreted carefully, particularly in older adults.

Study Methods and Key Findings

The cohort study used data from the English Longitudinal Study of Ageing (ELSA), a nationally representative sample of adults aged 50 and older. Participants underwent repeated assessments of episodic memory via immediate and delayed word recall tests, as well as verbal fluency tests such as animal naming tasks. Physical activity was measured objectively using wrist accelerometers worn continuously for eight days, capturing time spent in light activity, sedentary behavior, and sleep.

The strongest differences appeared in light physical activity rather than structured exercise, the researchers reported. Among participants aged 70 and older, those with slower memory decline averaged up to 20 additional minutes of daily light activity, equivalent to about 2.3 hours more per week. Light physical activity was defined as walking, household chores, or casual movement. The authors noted that such differences are clinically meaningful, as previous research suggests even modest reductions in daily activity are associated with higher mortality risk in older adults.

Previous research has linked physical activity to brain health. A study published in Nature found that walking 5,001 to 7,500 steps daily delayed cognitive decline in adults aged 50 to 90 [1]. Similarly, even low-intensity exercises like stretching have been shown to reduce Alzheimer’s risk and slow cognitive decline [2]. These findings underscore the importance of maintaining activity, but the new study highlights that decline in activity may itself be an early indicator of cognitive changes.

Researcher Insights on Reverse Causation

Bloomberg emphasized that the findings point to reverse causation as a plausible explanation for observed associations between physical activity and cognitive function. The lower activity levels seen in participants with faster memory decline may reflect long-term cognitive deterioration rather than a lack of exercise causing cognitive loss. She noted that differences of 10 to 20 minutes of light activity per day are not trivial, as they add up to one to two hours less activity per week, which prior observational research links to health and mortality risk.

The relationship is likely bidirectional, Bloomberg explained. Physical activity may support brain health, but cognitive decline can also shape activity patterns. The study adds caution to how observational evidence is interpreted, especially in later life, but does not negate the importance of exercise for reducing dementia risk. The researchers suggested that cognitive decline may gradually interfere with a person’s ability to plan, initiate, or sustain activity, and may coincide with social withdrawal, depressive symptoms, or frailty.

These findings align with a broader body of research on lifestyle and brain health. Social and cognitive activities, including reading and maintaining interpersonal networks, have been linked to slower frailty progression in older adults [3]. A separate study on daily activity patterns found that disrupted rest-activity rhythms were associated with brain volume loss in regions vulnerable to Alzheimer’s disease [4]. Such evidence underscores the interconnected nature of cognitive, physical, and social well-being in aging.

Implications and Study Limitations

The findings suggest that reduced movement could be an early sign of underlying brain changes rather than an independent cause of cognitive decline. Bloomberg noted that reduced physical activity is too nonspecific to serve as a marker of cognitive decline on its own, as it can result from physical illness, pain, depression, or mobility changes. However, it may be part of a broader pattern of changes indicating increased cognitive vulnerability in later life.

The study has several limitations. Participants in the accelerometer portion were healthier, wealthier, and more physically active than the general population, and they were predominantly white, which may limit generalizability to more diverse groups. Additionally, the observational design means the study cannot prove that cognitive decline directly causes inactivity. The authors called for caution in interpreting studies that link exercise with reduced dementia risk in older adults.

Other research supports the idea that physical activity remains important for brain health. Exercise has been shown to lower dementia risk through multiple mechanisms, including promoting neurogenesis and reducing inflammation. A large meta-analysis of 69 studies found that regular exercise and proper sleep significantly reduce the risk of cognitive decline [5]. Even light activities such as gardening, which provide both physical and mental health benefits, can support cognitive function [6].

Conclusion: What the Findings Mean for Aging Adults

The study does not negate the value of physical activity for brain health, according to Bloomberg. She advised that light physical activities such as walking, gardening, or household tasks are beneficial and sustainable for older adults. The best activity is one that is enjoyable and realistic enough to become part of daily life.

Bloomberg recommended that clinicians and researchers interpret observational links between exercise and dementia risk with caution, as reverse causation may play a role. For older adults, maintaining cognitive and physical activities remains advisable to support healthy aging. Additional research from the Yale University indicates that nearly half of seniors show improvements in cognitive or physical function over 12 years, challenging the notion that decline is inevitable [7]. Simple lifestyle changes, including staying active and engaged, can drastically reduce dementia risk [5].

References

1. NaturalNews.com. “Walking 5,000 steps a day could delay Alzheimer’s progression by years, study finds.” Patrick Lewis. November 4, 2025.
2. NaturalNews.com. “Even simple exercises like stretching could slash Alzheimer’s risk and boost brain health, studies show.” Cassie B. May 1, 2025.
3. NaturalNews.com. “Study: Social and Cognitive Activities Linked to Slower Frailty Progression in Older Adults.” June 4, 2026.
4. NaturalNews.com. “Study Links Disrupted Daily Activity Patterns to Brain Volume Loss in Older Adults.” May 7, 2026.
5. NaturalNews.com. “Simple lifestyle changes can drastically reduce dementia risk, study finds.” April 20, 2026.
6. NaturalNews.com. “STUDY: Gardening offers physical and mental health benefits for cancer survivors.” Evangelyn Rodriguez. January 20, 2025.
7. NaturalNews.com. “Study Finds Nearly Half of Seniors Show Cognitive or Physical Improvements Over 12 Years.” Morgan S. Verity. March 28, 2026.
8. Tony Buzan. “Brain boot camp: sharpen your memory in 7 days.”
9. Dr. Lisa Mosconi. “Brain Food: The Surprising Science of Eating for Cognitive Power.”