Objective: To determine by meta-analysis whether physical exercises are beneficial for people with dementia and related cognitive impairments.
Data sources: Published articles and nonpublished manuscripts from 1970 to 2003 were identified by using electronic and manual searches. Key search words included exercise, rehabilitation, activities of daily living, dementia, Alzheimer's disease, aged, and geriatrics.
Study selection: Reviewed studies were limited to randomized trials evaluating exercise in persons 65 years of age or older with cognitive impairment. Studies included quantitative results (means, standard deviations, t tests, F tests) for physical fitness, physical functioning, cognition, or behavior outcomes.
Data extraction: One reviewer extracted data on study characteristics and findings. Selected articles were evaluated for methodologic quality by 2 raters.
Data synthesis: A total of 2020 subjects participated in the 30 trials that met the inclusion criteria. Summary effects were computed using a fixed effects (Hedge's g(i)) model. Significant summary effect sizes (ES) were found for strength (ES=.75; 95% confidence interval [CI], .58-.92), physical fitness (ES=.69; 95% CI, .58-.80), functional performance (ES=.59; 95% CI, .43-.76), cognitive performance (ES=.57; 95% CI, 0.43-1.17), and behavior (ES=.54; 95% CI, .36-.72). The overall mean ES between exercise and nonexercise groups for all outcomes was .62 (95% CI, .55-.70).
Conclusions: Exercise training increases fitness, physical function, cognitive function, and positive behavior in people with dementia and related cognitive impairments.