A systematic review of urban green and blue spaces and cognitive function including discussion of mechanistic pathways

Abstract

Urban green and blue spaces (UGBSs) have been found to have health-enhancing properties (e.g. promotion of physical activity, improved social connectedness, and stress reduction). We examined the associations between UGBSs and cognitive function and aimed to identify any mechanistic pathways involving UGBSs and cognitive function. The initial search of four databases (MEDLINE, Embase, PSYCHInfo, and Web of Science) yielded 4838 studies when duplicates were removed to undergo abstract screening. Following abstract and full text screening, the included studies were classified as ‘observational’ (proximity to UGBSs,n= 28/35) or ‘interventional’ (n= 7/35). Of the included studies, 71.4% (n= 24/28) of ‘observational’ studies and 57.1% (n= 4/7) of ‘interventional’ studies found positive associations indicating that UGBSs are beneficial for cognitive function (i.e. enhance cognitive function, lower risk of cognitive impairment, or protect cognitive function). Overall, 71.4% (n= 20/35) of studies included within this review were considered to have a medium risk of bias. Current studies have identified relationships between UGBSs and cognitive function; however, further work is required globally to broaden our understanding and provide a reliable evidence base. Current literature has elucidated numerous mechanistic pathways by which UGBSs have the capacity to operate, including attention restoration theory and stress reduction theory. Advancing the evidence for the mechanistic pathways between UGBSs and cognitive function is required. This may advise future UGBS policies to improve the health and well-being of both the environment and the globally ageing population.