VO2max, running economy, and lactate threshold have long been established as physiological determinants of endurance performance. Strategies to optimally improve these parameters have therefore been of much interest to endurance athletes.
PURPOSE: To determine the effects of post-exercise passive heating strategies with hot water immersion and sauna suits on VO2max, running economy, and lactate threshold.
METHODS: Participants (see table for physical characteristics) were randomized into three standardized 3wk exercise training groups: 1) exercise training alone - control (N=10), 2) exercise training with immediate post-exercise hot water immersion (N=10), and exercise training with immediate post-exercise sauna suit (N=10). At baseline and post-program participants completed a running economy protocol and maximal exercise testing protocol to measure VO2max and lactate threshold. The running economy protocol consisted of three consecutive 5-minute stages: stage 1 = 4.6 mph, stage 2 = 5.0 mph, and stage 3 = 5.4 mph.
RESULTS: After 3wk, mean VO2max and lactate threshold changes in the sauna suit and hot water immersion groups were significantly greater (p < 0.05) when compared to the control group (see table). The hot water immersion group showed significant within-group improvements (p < 0.05) in economy between baseline and 3wk for all three stages (see table), although there were no between group differences (p > 0.05).
CONCLUSION: Both post-exercise passive heating strategies were equally effective at increasing VO2max and lactate threshold values. Additionally, despite the absence of between-group statistical significance, preliminary evidence suggest post-exercise hot water immersion may be a more effective strategy at improving running economy relative to wearing a sauna suit after exercise.