Acute exercise‐induced improvements in cognition: Role of cerebral blood flow and metabolism

Physical activity is widely recognized for its ability to promote brain health, with acute exercise transiently enhancing cognition and long-term training attenuating cognitive decline. However, the mechanisms underlying these benefits remain incompletely understood. Cerebral blood flow (CBF) has traditionally been considered central to exercise-induced cognitive improvements, given the brain's dependence on a continuous supply of oxygen and glucose. Yet, accumulating evidence indicates that changes in global CBF alone cannot fully explain enhanced cognitive performance. Instead, regional CBF responses through neurovascular coupling, as well as cerebral metabolism - including oxygen extraction, glucose utilization and lactate uptake - are likely more critical determinants of brain function in response to exercise. Importantly, substantial individual differences exist in these responses. While some individuals experience robust cognitive gains from identical exercise regimens, others show little or no benefit. Emerging evidence suggests that variability in glucose tolerance, lactate dynamics and exercise capacity may underlie this heterogeneity, reflecting differences in metabolic responses and cerebrovascular regulation. For example, impaired glucose utilization might be linked to diminished exercise-induced cognitive improvement, whereas lactate uptake appears to support high-intensity exercise-related gains. These findings highlight that the cognitive effects of exercise are not uniform, but rather influenced by individual physiological characteristics. This review therefore emphasizes the integrative regulation of CBF and metabolism as key factors mediating exercise-induced cognitive improvements, while emphasizing the importance of inter-individual variability. Understanding why some individuals benefit more than others is essential for adapting exercise prescriptions to maximize brain health across diverse populations.