Physical activity and cognitive function in individuals over 60 years of age: a systematic review

Background: It is unclear whether physical activity in later life is beneficial for maintenance of cognitive function. We performed a systematic review examining the effects of exercise on cognitive function in older individuals, and present possible mechanisms whereby physical activity may improve cognition. Methods: Sources consisted of PubMed, Medline, CINAHL, the Cochrane Controlled Trials Register, and the University of Washington, School of Medicine Library Database, with a search conducted on August 15, 2012 for publications limited to the English language starting January 1, 2000. Randomized controlled trials including at least 30 participants and lasting at least 6 months, and all observational studies including a minimum of 100 participants for one year, were evaluated. All subjects included were at least 60 years of age. Results: Twenty-seven studies met the inclusion criteria. Twenty-six studies reported a positive correlation between physical activity and maintenance or enhancement of cognitive function. Five studies reported a dose-response relationship between physical activity and cognition. One study showed a nonsignificant correlation. Conclusion: The preponderance of evidence suggests that physical activity is beneficial for cognitive function in the elderly. However, the majority of the evidence is of medium quality with a moderate risk of bias. Larger randomized controlled trials are needed to clarify the association between exercise and cognitive function and to determine which types of exercise have the greatest benefit on specific cognitive domains. Despite these caveats, the current evidence suggests that physical activity may help to improve cognitive function and, consequently, delay the progression of cognitive impairment in the elderly.