Cognitive Performance following Single- or Multi-Session Exercise Intervention in Middle Age: A Systematic Review.

Background: Research in modifiable behaviors, like exercise, on risk for dementia is increasing. Although many studies focus on older adults, brain pathology for Alzheimer's Disease can begin in middle age, suggesting an ideal target for intervention.

Methods: We conducted a systematic review from exercise intervention studies on cognitive function among healthy, middle-aged participants (45-65). We searched multiple databases (PubMed, PsycINFO, MEDLINE, Cochrane Central Register of Controlled Trials, Google Scholar) for studies using standard, validated, neuropsychological measures following either single- or multi-session interventions in cognitively-unimpaired, middle-aged adults.

Results: We identified 13 eligible studies. There was notable heterogeneity across studies, with varying design, measures, interventions, and results. Results from single-session studies showed improvement in response inhibition, while results for cognitive flexibility were mixed. No significant changes were found on measures of attention, working memory, or processing speed. Results from multi-session studies were more varied. Verbal memory was found to improve while performance on tests of attention and working memory, processing speed, and executive function were mixed.

Conclusion: Importantly, for both single-session and multi-session studies, there was no standard set of neuropsychological tests administered, making it more difficult to synthesize the findings into a single narrative. We end with a discussion on future directions and implementation.