The effect of physical activity interventions on cognitive function of older adults: A systematic review of clinical trials.

Prevalence of dementia or of milder form of cognitive impairment is increasing and a pharmaceutical treatment remains pending. These facts underline the need of identifying modifiable factors and targeted interventions that could reduce the incidence or control disease progression. Physical activity (PA) has been shown to have a beneficial effect on cognitive function, however findings to date remain controversial. The aim of this systematic review is to summarize the most recent data from clinical studies investigating the relationship between cognitive impairment and PA in adults older than 60 years of age. For this purpose, PubMed, Scopus and Google Scholar, search was conducted, and a total of thirty-five studies were selected to review. Eleven studies investigated the effect of PA on individuals without cognitive impairment and seven of them presented some significant improvement, mostly on specific cognitive domains and only one in global cognition. Fourteen studies included populations with mild cognitive impairment (MCI) and twelve of them reported significant improvements in cognitive function. The majority of them presented a beneficial effect on global cognition and executive function. Finally, nine studies investigated interventions on populations with a diagnosis of dementia and only four of them showed any cognitive benefit following their interventions. There was no consistent observed association of a specific type of exercise and greater improvement or improvement in certain domains of cognition nor was there a minimum duration of intervention required for the improvements to take effect. In conclusion, the majority of the latest published literature suggests a protective role of PA on cognitive function. People with MCI seem to benefit the most from PA interventions, benefits in people with normal cognition are more subtle and harder to detect, while findings from studies in people with dementia remain contradictory. As findings are not currently in total agreement, further long-term prospective intervention studies are required in order to elucidate the reasons of this heterogeneity.