Prefrontal Hemodynamics and Working Memory After Exhaustive Aquatic Exercise

This study compared prefrontal cortex hemodynamics and working memory performance following exhaustive aquatic exercise between endurance athletes and physically active individuals. Twenty-two healthy male participants aged 18-30 years, including 10 endurance athletes and 12 physically active controls, completed an incremental stepping exercise to exhaustion during head-out water immersion. The exercise was performed on a 20-cm step at xiphoid-level water depth, with cadence beginning at 18 steps/min and increasing by 2 steps/min every 30 seconds. Approximately 5 minutes after exercise, participants completed a seated 2-back working memory task while prefrontal cortex hemodynamic responses were assessed using functional near-infrared spectroscopy (fNIRS). Cognitive performance and prefrontal hemodynamic responses were compared between the two groups.

Inclusion Criteria: * Healthy males aged 18-30 years. * Endurance athletes or physically active individuals according to the study's predefined group criteria. * Able to perform the aquatic stepping exercise protocol and complete the 2-back working memory task. * Provided written informed consent to participate. Exclusion Criteria: * Presence of cardiovascular, pulmonary, neurological, metabolic, musculoskeletal, or psychiatric conditions that could affect exercise performance or cognitive assessment. * Use of medications or substances that could influence cognitive function, cardiovascular responses, or exercise tolerance. * Inability to safely perform the aquatic exercise protocol or complete the study procedures.