Effects of exercise interventions on executive function in old adults with mild cognitive impairment: A systematic review and meta-analysis of randomized controlled trials.

Aims: To assess the effect of exercise interventions on subdomains of executive function (EF) in older adults with mild cognitive impairment (MCI).

Methods: Nine electronic databases were comprehensively searched from their inception to February 2021. Randomized controlled trials examining the effect of exercise training on EF in MCI were included.

Results: Twenty-four eligible articles involving 2278 participants were identified. The results showed that exercise interventions had positive benefits on working memory, switching and inhibition in MCI. Subgroup analysis based on exercise prescriptions revealed that both aerobatic exercise and mind-body exercise had similar positive effect size on working memory. However, only mind-body exercise had significant effect on switching. Exercise training with moderate frequency (3-4 times/week) had larger effect size than low frequency (1-2 times/week) and only moderate frequency had positive benefits on switching. Both short (4-12 weeks), medium (13-24 weeks) and long (more than 24 weeks) exercise duration significantly ameliorate working memory and switching, however with short duration having slight larger effect sizes than medium and long.

Conclusion: Exercise significantly improves three subdomains of EF in MCI, especially mind-body exercise. Exercise training sticking to at least 4 weeks with 3-4 times a week tends to have larger effect size.