The Effects of Cold vs. Hot Water Immersion on Exercise Recovery: Which Strategy is Best?

Introduction: Hot and cold water immersion (HWI and CWI respectively) are both options for recovery from intense and exhaustive exercise. The current research shows mixed results with some studies indicating that HWI and CWI have no effect on subsequent exercise performances while some point to improvements and/or decrements. The purpose of this research was to further the direct comparisons between HWI and CWI as methods of recovery for lower body exercise. Methods: Subjects (n=9) were moderately active healthy individuals aged 16-31. To analyze recovery effectiveness, an exhaustive lower body workout was performed followed immediately by one of the recovery modalities and followed again 24 hours later by the same exhaustive workout. The workout included a 70% VO₂max running trial to fatigue, a Wingate (30 second cycling test), and an 80% of leg press 1 rep max (1RM) repetitions to fatigue test. HWI was performed for 12 minutes at 40°C while CWI was performed for 12 minutes at 12°C. Results: A Chi-square test for independence indicated a significant association between recovery method (CON vs. HWI vs. CWI) and overall individual exercise performance, χ² (1, n = 81) = 7.264, p < .05, phi = .299. The proportion of individuals who exhibited a positive change in exercise performance following either HWI or CWI was significantly greater from the proportion of CON individuals (p < 0.05). Following HWI and CWI recovery methods, there were 63.0% and 66.7%, respectively, of individuals that exhibited maintained or increased exercise performance. In comparison, in the CON recovery condition, there were 33.3% of individuals who exhibited maintained or increased exercise performance. The Phi coefficient value (phi = .299) indicates a medium-to-large effect size. Conclusion: The main finding of this study was that there is a higher likelihood of maintained or improved overall lower body performance with either HWI or CWI post-exercise compared to control with a recovery period of about 24 hours. This preliminary finding is a step forward in furthering the research into how HWI and CWI can benefit recovery.