Effects of physical exercise on executive function in cognitively healthy older adults: A systematic review and meta-analysis of randomized controlled trials: Physical exercise for executive function

Objective To assess the effect of physical exercise interventions on executive function in cognitively healthy adults aged 60 years and older. Methods Four electronic databases, the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Web of Science and Embase, were comprehensively searched from their inception to November 25, 2019. Randomized controlled trials (RCTs) examining the effect of physical exercise on executive function in cognitively healthy older adults were included. Results Twenty-five eligible trials with fair methodological quality were identified. Compared to a no-exercise intervention, physical exercise had positive effect on working memory (Hedge's g=0.127, p<0.01, I2= 0%), cognitive flexibility (Hedge's g=0.511; p=0.007, I2=89.08%), and inhibitory control (Hedge's g=0.136; p=0.001, I2=0%) in cognitively healthy older adults. The moderator analysis indicated that more than 13 weeks of aerobic exercise significantly improved working memory and cognitive flexibility, and intervention lasting more than 26 weeks significantly improved inhibition; mind-body exercise significantly improved working memory. No significant effect on planning or semantic verbal fluency (SVF) was found. Conclusion Regular physical exercise training, especially aerobic exercise and mind-body exercise, had positive benefit for improving working memory, cognitive flexibility and inhibitory control of executive function in cognively healthy older adults. Further well-designed RCTs should focus on the impact of specific exercise forms with a standardized exercise scheme on executive function in cognitively healthy older adults.