Effects of multicomponent exercise on cognitive function in persons with mild cognitive impairment: A systematic review and meta-analysis

Background: Multicomponent exercise has the potential to improve cognitive function in people with mild cognitive impairment. However, the effects of multicomponent exercise on specific cognitive subdomains in mild cognitive impairment and the optimal combination of exercise components remain unclear. Objective: This systematic review aimed to (a) investigate the effects of multicomponent exercise on different cognitive subdomains in people with mild cognitive impairment and (b) investigate the effects of different combinations of multicomponent exercise on global cognition in people with mild cognitive impairment. Design: A systematic review and meta-analysis. Methods: Six electronic databases, including PubMed, Medline, EMBASE, Web of Science, Cochrane Library, and CINAHL were systematically searched from inception to January 1st, 2023. Randomized controlled trials assessing the effect of multicomponent exercise interventions on cognitive function in people with mild cognitive impairment were included. The risk of bias was assessed using the Cochrane collaborative bias assessment tool. A random-effects model was used to calculate standardized mean difference. Subgroup analyses, meta-regression, and sensitive analysis were performed. If a meta-analysis was not feasible, studies were synthesized narratively. Results: Twenty studies were identified for systematic review and meta-analysis. Multicomponent exercise significantly improved global cognition [SMD = 1.04; 95 % confidence interval (CI): 0.53, 1.55], cognitive flexibility (SMD = − 1.04; 95 % CI: − 1.81, − 0.27), processing speed (SMD = 0.43; 95 % CI: 0.04, 0.82), verbal fluency (SMD = 0.38; 95 % CI: 0.13, 0.63), attention (SMD = − 0.90; 95 % CI: − 1.68, − 0.12) and memory (SMD = 0.36; 95 % CI: 0.04, 0.69) in mild cognitive impairment. The multicomponent exercise including cardiovascular (exercise that promotes cardiovascular health, such as endurance training or aerobic exercise) and motor (exercises that improve physical abilities, such as balance, coordination, agility, flexibility, etc.) components positively affected global cognition in people with mild cognitive impairment (SMD = 1.06; 95 % CI: 0.55, 1.57). Conclusions: The findings of this study suggest that multicomponent exercise has a positive impact on various cognitive domains, including global cognition, cognitive flexibility, processing speed, verbal fluency, attention and memory in mild cognitive impairment. Specifically, the combination of exercises including cardiovascular and motor components was found to be effective in improving global cognition. However, further research is needed to investigate the optimal frequency and intensity of the multicomponent exercise intervention, and more detail about exercise combinations of the motor component (not classified in this study) for individuals with mild cognitive impairment. Registration: The protocol was registered on PROSPERO (CRD42023400302).