Lactate Clearance Among Competitive Swimmers

Blood lactate levels serve as an indirect marker for biochemical events such as fatigue within exercising muscle and can affect performance. PURPOSE: To evaluate the effects of various cool-down protocols on lactate clearance in competitive swimmers, with an additional focus on examining sex-based differences in lactate production dynamics. METHODS: Twenty-three NCAA Division I swimmers (9 males; 14 females) participated in the lactate collection during the swim meet. Participants completed a single event (100 or 200 meters) in one of four strokes (backstroke, breaststroke, butterfly, or freestyle). Blood lactate concentrations were measured via fingertip sampling both immediately post-race and post-cool-down, utilizing the Nova Biomedical Lactate Plus analyzer and corresponding test strips. Swimmers were randomly assigned to one of two standardized cool-down protocols: 400 meters of easy swimming or 8x50 meters alternating 2 swims and 1 kick. Independent sample t-tests were conducted to compare the effects of different cool-down protocols and to investigate sex-based differences in lactate removal rates and peak lactate concentrations (Lamax). RESULTS: No significant difference was observed in lactate removal rate between the two cool-down types (-3.6 vs -3.3 mmol/L, p = 0.72). Females exhibited a faster lactate removal rate compared to males (-4.3 vs -2.2 mmol/L, p = 0.003) with no significant difference in cool-down duration (9 min, 30 sec vs 10 min, 40 sec, p = 0.34). Additionally, females had lower Lamax than males (12.9 vs 15.6 mmol/L, p = 0.001). CONCLUSIONS: Findings of this study suggest that the type of cool-down does not significantly impact lactate removal rate in swimmers. However, significant sex-based differences were identified, with females exhibiting more rapid lactate clearance and lower peak lactate (LAmax) values compared to males. These differences may be influenced by factors such as fiber composition and aerobic capacity. However further research is needed to fully understand the potential cause for this lactate response, whether it its due the difference in training cycles in males and females or physiological difference in males and females.