Exercise Reduces Cognitive Decline in Adults at Risk for Alzheimer's

Older adults with amnestic mild cognitive impairment (aMCI), a precursor to Alzheimer’s disease, may be able to slow the decline in memory and cognitive function by incorporating regular physical activity into their routines, according to findings from a large clinical trial conducted across multiple research centers in the United States.

The study, known as EXERT (Exercise in Adults with Mild Memory Problems), involved nearly 300 sedentary older adults diagnosed with aMCI. Participants were randomly assigned to engage in either moderate-high intensity aerobic training or lower-intensity stretching, balance and range of motion activities. Each participant exercised under the supervision of a YMCA trainer three to four times per week for a year. Their cognitive function and brain volume were regularly assessed throughout the trial period.

Comparative benefits of exercise

Results published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association showed that cognitive performance remained stable over 12 months for individuals in both exercise groups. This finding was particularly notable because individuals with aMCI typically experience measurable cognitive decline over the same timeframe.

To further contextualize the effects of exercise, researchers compared the EXERT participants’ outcomes to a separate cohort of similarly diagnosed individuals who only received usual care – such as medical management and routine check-ups – without any added physical activity program. The comparison revealed that participants in the exercise arms of the EXERT trial exhibited significantly less cognitive decline than those in the non-exercise group.

In addition to cognitive outcomes, imaging data suggested that participants in the exercise groups showed reduced brain volume loss, particularly in the prefrontal cortex, a brain region involved in executive function and decision-making.

Implications for Alzheimer’s prevention

The findings contribute to a growing body of evidence suggesting that lifestyle interventions, such as exercise, may serve as viable strategies to delay or prevent the onset of dementia in at-risk populations. While previous studies have provided mixed results, the design and scale of the EXERT study lend weight to the conclusion that exercise can play a protective role in brain health among older adults with mild cognitive symptoms.

“This is a critical time to intervene in this population, because they don’t have dementia yet, but are at a very high risk,” said Dr. Aladdin Shadyab.

Interestingly, the researchers observed cognitive stability across both exercise intensities, indicating that even low intensity activity might confer benefits. This aspect of the findings could have implications for designing accessible exercise interventions tailored to older adults who may not be able to perform high-intensity workouts.

“While there’s still a lot to learn, these findings show that regular intensity exercise, even at low intensity, could go a long way toward helping older adults slow or delay cognitive decline, and this is promising news for those who are at high risk for dementia,” added Shadyab.

Study design and context

The EXERT study was coordinated by the Alzheimer’s Disease Cooperative Study (ADCS), based at the University of California San Diego, in collaboration with Wake Forest University School of Medicine. The trial stands out as one of the first large-scale studies to deliver exercise interventions through a community partner – the YMCA – bringing the research closer to real-world settings.

The EXERT trial represents a meaningful step toward identifying non-pharmacological approaches that could be implemented at the community level to support older adults facing memory challenges. However, as the study only included individuals with aMCI, the findings may not be directly applicable to the general population or those already diagnosed with Alzheimer’s dementia.

Reference: Baker LD, Pa JA, Katula JA, et al. Effects of exercise on cognition and Alzheimer’s biomarkers in a randomized controlled trial of adults with mild cognitive impairment: The EXERT study. Alzheimer’s Dementia. 2025;21(4):e14586. doi: 10.1002/alz.14586

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