Association between Physical Activities and Dementia: A Systematic Review

Abstract

Background: Dementia (major neurocognitive disorder) is a leading cause of disability and dependence in the elderly, posing significant social, physical, and economic challenges. With no effective cure currently available, research has shifted toward preventive approaches. Physical exercise has emerged as a promising strategy, offering physiological benefits such as increased cerebral blood flow, elevated neurotrophic factor production, and enhanced brain volume. However, it remains uncertain whether these neurobiological and structural changes translate into meaningful cognitive preservation.

Objective: This systematic review synthesizes evidence from 17 randomized controlled trials (RCTs) to evaluate the impact of physical activity on global cognition, memory, and executive function in older adults.

Methods: A comprehensive search (January 2000–March 2025) of PubMed, Google Scholar, and EMBASE was conducted following PRISMA guidelines. We included RCTs (in English or with English translation) examining aerobic and/or resistance exercise interventions (≥150 minutes/week for ≥12 weeks) in adults across cognitive spectra from normal cognition to mild cognitive impairment (MCI) and mild-to-moderate dementia. Trials without a usual-activity control, with confounding co-interventions (e.g., cognitive training or diet supplements), in severe dementia, or with exercise duration <12 weeks were excluded. Data on cognitive outcomes were extracted and cross-checked for relevant studies.

Results: Seventeen RCTs met inclusion criteria. In cognitively normal or MCI individuals, exercise was associated with modest improvements in cognitive measures. Specifically, several studies reported better global cognition scores in exercise groups at the end of the intervention, though benefits often diminished after exercise cessation. Memory improvements were observed mainly in participants with normal cognition or MCI, whereas trials in mild-to-moderate dementia generally showed no memory benefit. Executive function gains were noted following both aerobic and resistance training, with some evidence suggesting greater effects with supervised or higher-intensity protocols.

Conclusions: Physical exercise confers small cognitive benefits, particularly in those who are cognitively intact or mildly impaired. Extended follow-up indicates these gains may taper off once exercise is stopped, underscoring the need for sustained activity to maintain benefits. Ongoing engagement in regular exercise could help preserve cognition and potentially delay dementia onset in the aging population.

Keywords: Cognition, Dementia, Exercise, Physical Activity