A pre-registered systematic review and network meta-analysis of 227 randomised controlled trials compared exercise-only programmes against exercise combined with cognitive training or other lifestyle components (Exercise-Plus) in adults over 60 without dementia. Exercise-only interventions produced statistically significant improvements across all three cognitive domains — executive function, memory, and processing speed — versus control. Exercise-Plus outperformed control only for memory, yet paradoxically beat exercise-only for executive function and processing speed in the network meta-analysis, creating a mixed picture that complicates straightforward clinical guidance.
The counterintuitive result — that adding cognitive or lifestyle components to exercise helps some domains versus exercise-only, yet Exercise-Plus underperforms exercise-only as a package against control — likely reflects the heterogeneity of what counts as an 'Exercise-Plus' programme across 67 trials, diluting effect estimates. This is one of the largest cognitive exercise meta-analyses conducted to date, lending its broad Exercise-Only finding considerable statistical weight. For adults and clinicians, the actionable takeaway is robust: structured exercise reliably protects cognitive function in the pre-dementia years, and complexity of programme design may not be necessary to achieve benefit. The findings align with prior meta-analyses showing aerobic exercise drives hippocampal volume increases and executive function gains. Limitations include inevitable heterogeneity in exercise type, intensity, and duration across 227 trials. The field still needs dose-response data to determine optimal exercise prescriptions for cognitive longevity.
