Cardiorespiratory Fitness and Neurophysiological Indices of Working Memory Maintenance in Young Adults.

Working memory is a crucial component of cognitive performance, supporting well-being, mental health, and successful personal and academic endeavors. Working memory performance and capacity peak during young adulthood, a critical period for managing increased life challenges. Emerging evidence indicates that cardiorespiratory fitness holds potential to enhance working memory performance; however, the underlying mechanisms remain unclear. This study examined the association between cardiorespiratory fitness and neurophysiological markers of cognitive control during a task requiring working memory maintenance. Young healthy adults (N = 112) completed a submaximal ergometer test to estimate cardiorespiratory fitness. Working memory maintenance was assessed using the Sternberg task under low and high cognitive loads, while event-related potentials (ERP) components (cue-P300, CNV, and probe-P300) were recorded. In addition, an immediate free recall task was administered. Path analysis revealed that higher cardiorespiratory fitness was significantly associated with better accuracy in the Sternberg task exclusively under high cognitive load (β = 0.21, p = 0.03). In the high load condition, higher negativity of the contingent negative variation (CNV) amplitude was significantly associated with higher fitness levels (β = -0.20, p = 0.03) and with better performance on the immediate free recall task (β = -0.23, p = 0.02), suggesting enhanced neurophysiological preparatory processes and dominance of proactive cognitive control strategy in fitter individuals. Cue-P300 and probe-P300 did not show significant associations with cardiorespiratory fitness nor working memory performance. These findings underscore the role of proactive cognitive control in mediating the benefits of cardiorespiratory fitness on cognitive performance.