Effects of an acute bout of exercise on cognitive function in adults with cognitive impairment: A systematic review with meta-analysis of randomised controlled trials

ObjectiveExamine the effects of an acute bout of physical exercise on cognitive function in adults with cognitive impairment (CI). DesignSystematic review with meta-analysis of randomised controlled trials (RCTs) that investigated the effects of a single exercise session on cognitive function. Dual data abstraction, risk of bias assessment (RoB2) and strength of evidence assessment (GRADE) were conducted. Results were pooled using the inverse variance heterogeneity (IVhet) model or synthesised narratively. Data sourcesSix databases from inception to July 2024: (1) PubMed, (2) SportDiscus, (3) PsychINFO, (4) Cochrane Central, (5) PEDro, (6) Embase. Eligibility criteriaRCTs of acute exercise with male/female participants, aged 18+, and physician diagnosed or self-reported CI. Results15 studies (8 parallel group, 7 crossover) representing 500 participants were included, 10 in the meta-analysis. Acute exercise significantly improved executive function ("moderate" evidence, 9 studies, 330 participants, g=0.33, small effect, 95%CI [0.07, 0.59], p=0.01, I{superscript 2}=26.77, 95%CI [00.00, 65.82]. However, this was only for high risk of bias/crossover studies. Improvements in direction of benefit but non-significant for reaction time ("very low" evidence, 7 studies, 271 participants, g=0.17, small effect 95%CI [-0.20, 0.54], p=0.36, I{superscript 2}=50.18, 95%CI [00.00, 78.88]. Improvements in memory, but mixed evidence for attention, information processing and motor memory noted via narrative assessment. ConclusionIn a healthy population, acute exercise improves cognition. For adults with CI, we found evidence of improvement in executive function, reaction time and memory. However, the review was limited by the inclusion of studies primarily with "high"/"some concerns" for bias and "very low"/"low" strength of evidence. Summary boxO_LIChronic exercise interventions have demonstrated significant improvements in cognition for healthy and cognitively impaired adults (1,2) C_LIO_LIAcute exercise improves cognitive function in healthy adults (3-5) but evidence for the beneficial effects of acute exercise in cognitively impaired adults is uncertain. C_LIO_LIOur meta-analysis of 10 randomised controlled trials found that acute exercise improves executive function (small effect, moderate strength evidence) in adults with cognitive impairment. C_LIO_LIIt may also lead to improvements in reaction time (small effect, very low strength evidence) and memory (low strength evidence). C_LI