Abstract
Background. Systematic reviews show a favourable relationship between physical activity (PA) and cognition in children and youth, but the predominance of observational study designs limits causal inferences. This systematic review will fill a research gap by including only studies that employed randomized controlled designs. Methods. PRISMA guidelines were followed after registration in PROSPERO. Inclusion criteria were: randomized controlled design; manipulated PA once (acute) or more (chronic), compared to no PA or other types/durations/intensities of PA, in apparently healthy children (1 month-17 years); and examined cognitive function, brain function, or brain structure outcomes. Study screening and data extraction were performed in duplicate. Results. 84 studies from 83 manuscripts were included (N=12,600 unique participants; Mrange=0.77-17 years). Most studies were rated as having low risk of bias. Compared to controls, most studies (n=52) reported at least one favourable effect of PA on cognitive function and few (n=6) reported an unfavourable effect. Examining all cognitive function outcomes within each study, PA had mostly no effect (nacute=29, nchronic=47) or a mix of favourable and no effect (nacute=20, nchronic=27). For brain function, acute PA was associated with no change (n=2) whereas chronic PA was associated with a mix of increases, decreases, or no change (n=3). For brain structure, two overlapping studies found either favourable or no effects of chronic PA. Discussion. In children and youth, PA is unlikely to be detrimental to brain health and it may confer some benefits. More research is needed to better understand the impact of PA on brain structure and function.Acknowledgments: The Organix Foundation and the Children's Hospital of Eastern Ontario Foundation