Effects of contrast water therapy on performance, circulatory function, and fatigue in collegiate freestyle swimmers

This study aimed to examine the effects of contrast water therapy (CWT) on recovery following high-intensity interval training in competitive collegiate swimmers. Fifteen male freestyle swimmers (mean age: 19.3 ± 1.1 years) participated in a crossover design, performing five 100-meter maximal-effort intervals under two conditions: CWT and passive rest (PAS). Each session included standardized warm-up, pre- and post-intervention measurements of blood pressure (BP), blood lactate concentration (LA), and subjective fatigue (FAS), followed by a second interval set. CWT consisted of 10 cycles of hot (40–41 °C, 60 s) and cold (20–21 °C, 30 s) full-body immersion. Performance metrics—swim time, stroke count, stroke length, and stroke velocity—were recorded during both interval sets. The results showed no significant differences between CWT and PAS in swim performance or blood pressure. However, a significant interaction was observed in stroke length during the first interval set, indicating a potential subtle benefit of CWT on swimming mechanics. Importantly, blood lactate concentrations were significantly lower after CWT compared to PAS (p < .001), and subjective fatigue was also reduced. These findings suggest that CWT promotes metabolic recovery, likely through enhanced peripheral circulation and lactate clearance, without negatively affecting cardiovascular parameters. Although CWT did not enhance immediate performance, its ability to reduce physiological and perceptual fatigue indicates its value in managing accumulated fatigue during training cycles. In conclusion, contrast water therapy appears to be a practical and effective recovery strategy for competitive swimmers, especially in supporting lactate clearance and reducing fatigue following high-intensity training. Future studies should explore optimal immersion protocols and assess long-term benefits across varied performance levels.