Exercise and cognitive aging: a meta-analysis of macrovascular cerebral blood flow and cognitive function in older adults

BACKGROUND: Cognitive decline is a major public health challenge in aging populations, closely linked to cerebral blood flow (CBF) reductions. While exercise is suggested to improve cognitive function and cerebrovascular health, its precise effects remain unclear. METHODS: A systematic review and meta-analysis were conducted on studies published up to January 2024 using PubMed, Web of Science, ScienceDirect, Embase, Cochrane, PsycINFO, ClinicalTrials.gov. A total of 57 studies on cognitive function and 12 on CBF were included, focusing on randomized controlled trials (RCTs) or controlled trials. Standardized mean differences (SMDs) and weighted mean differences (WMDs) were calculated using fixed- or random-effects models. Regression analysis examined the association between CBF and cognitive outcomes. RESULTS: Exercise interventions significantly improved cognitive function (SMD = 0.52, 95% CI [0.31, 0.74], P < .001), particularly in inhibitory control, switching function, memory, and verbal fluency. Additionally, exercise increased middle cerebral artery velocity (WMD = 1.88, 95% CI [0.08, 3.67], P < .05) while reducing resting heart rate and pulse index. Higher CBF was positively correlated with cognitive performance, particularly memory and verbal fluency. CONCLUSION: Exercise enhances cognitive function in older adults by improving macrovascular CBF and cardiovascular efficiency. The positive effects of exercise on macrovascular CBF, as demonstrated by increased MCAv and reduced PI, play a crucial role in promoting cognitive health in the elderly. These findings support structured exercise programs as a non-pharmacological intervention for promoting brain health and delaying cognitive decline.