Cardiorespiratory fitness modulates the effect of acute exercise on vigilance performance in trained soldiers.

Cardiorespiratory fitness (CRF) is known to influence cognitive performance, particularly in tasks requiring sustained attention. However, the acute effects of high-intensity exercise on vigilance performance across different CRF levels remain underexplored. This study examined the impact of CRF level and a single bout of maximal incremental running on vigilance. Thirty-four male soldiers were assigned to either high- or low-CRF groups (n = 17 each). Participants performed a psychomotor vigilance go/no-go task at rest and immediately following exercise to exhaustion. Reaction time (RT), commission errors (CE), and omission errors (OE) were recorded and analyzed using repeated-measures ANOVA. Both groups showed improved RT after exercise compared to baseline. Participants with higher CRF consistently exhibited faster RTs across all task blocks. However, the low-CRF group demonstrated a greater magnitude of improvement post-exercise, suggesting a larger acute response to exercise. CRF modulates the cognitive effects of acute high-intensity exercise. Although all participants benefited, individuals with lower CRF showed relatively larger improvements in vigilance performance. These findings have implications for enhancing cognitive readiness in physically demanding settings, such as military operations.