In this post we are going to talk about post-exercise cold-water immersion and if it does have any effect. This post is based on the James R. Broatch, Aaron Petersen and David J. Bishop article “The Influence of Post-Exercise Cold-Water Immersion Adaptive Responses to Exercise: A Review of the Literature”.
Recovery from exercise refers to the restoration of the body’s physiological and psychological processes to a pre-fatigue state and performance level. A large body of research has focused on modalities designed to hasten recovery, with one of the most prevalent techniques being cold-water immersion (CWI). However, given the wide-spread use of CWI as a recovery modality, as well as the contrasting findings reported to date, clarification of the effects of CWI on the skeletal muscle adaptations to exercise training in humans is warranted.
What is cold-water immersion or CWI?
Cold-water immersion has emerged as a popular cryotherapy tool aimed at enhancing recovery following training and competition. Typically utilised following exercise, it involves the immersion of all or part of the body in cold water, with an intended therapeutic outcome.Although an optimal prescription for post-exercise CWI does not currently exist, water temperatures cooler than15°C and immersions of at least 10 min are typically utilised.
Post-exercise CWI is believed to limit, and speed there covery of, exercise-induced decrements in functional capacity and exercise performance. For a detailed review of the effects of CWI on the recovery from exercise,the reader is referred to a review on this topic. Briefly, many studies have demonstrated beneficial improvements in muscle strength, aerobic exercise performance, markers of exercise-induced muscle damage, inflammation, muscle soreness and perceptions of fatigue when CWI was implemented as a recovery technique. However, CWI has also been demonstrated to have no influence, or even a detrimental effect on similar measures, highlighting the equivocal nature of CWI research. The lack of consistency in the observed effects of CWI is commonly attributed to methodological discrepancies between studies, such as the immersion and or exercise protocols used, as well as the performance outcomes measured.
Single session – after 3 hours
Four studies have investigated the effects of post-exercise CWI on signalling responses associated with mitochondrial biogenesis in humans (Fig.2). CWI administered after a single session of high-intensity running or cycling increased PGC-1 alpha RNA content in a cooled lower limb (up to*9.0-fold), which was larger than the response in the contralateral and non-cooled control limb (up to*5.0-fold). Furthermore, these CWI-induced increases in PGC-1 alpha RNA may occur independent of a preceding exercise stimulus, and systemically. More recently, a similar increase (*7.5-fold) in PGC-1 alpha RNA content was observed following a single session of sprint-interval cycling and post-exercise CWI. This was, however, not significantly larger than the increase seen in the control condition (*5.4-fold), suggesting the effects of CWI on PGC-1 alpha RNA may be more pronounced following lower-intensity exercise. Despite the CWI-induced increases in PGC-1 aplha RNA reported in Fig.2, CWI appears to have no effect on the mRNA content of other proteins associated with PGC-1 alpha and mitochondrial adaptations (at least within 3-h post-exercise). Alternatively, it is possible that the 3-h-postrecovery biopsy time point may not have adequately captured the time course of changes in mRNA content of these proteins.
Endurance Exercise Training
A number of studies have investigated the merit of regular post-exercise CWI during an endurance training period (i.e., 3–6 weeks) (Fig.3). An attenuation of endurance performance and maximal oxygen uptake was observed following 4–6 weeks of regular post-exercise CWI (5°C for 2920 min), as compared with a passive control. In contrast, subsequent research employing more commonly utilised immersion protocols (e.g., 10–15°C CWI for 10–15 min) has reported minimal effects of regular CWI on endurance training adaptations. Forexample, regular CWI during 3–4 weeks of intense cycling training was shown to have negligible or slightly beneficial effects on cycling performance. In support of this, regular CWI following sprint-interval cycling had no effect on the lactate threshold, maximal oxygen uptake, and peak aerobic power. However, conclusive evidence either supporting or refuting the merit of CWI on adaptations to endurance exercise training is lacking. As such, a number of studies have investigated the effects of post-exercise CWI on molecular markers of endurance-related adaptations in human skeletal muscle.
Evidence for a positive effect of post-exercise CWI on endurance adaptations is scarce. Despite reported short-term increases in markers of mitochondrial biogenesis following a single session of post-exercise CWI , regular post-exercise CWI appears to have little to no effect on long-term adaptations. Considering the well established effects of cold on mitochondrial adaptations in animal models, it is possible that the CWI protocols used to date do not providea large-enough cold stimulus, and longer and/or colder immersion may be needed to elicit significant alterations in mitochondrial adaptations in human skeletal muscle. However, apart from early work by Yamane, it is important to note that no research has reported a negative effect of post-exercise CWI on markers of adaptation to endurance exercise or exercise performance. As such, current evidence suggests no reason to incorporate CWI into an endurance training programme if the goal is toaugment exercise-induced mitochondrial adaptations.
It is also difficult to make clear conclusions and recommendations regarding the effects of CWI on adaptations to resistance training. Studies have reported either no effect or a negative effect of CWI on key resistance training adaptations such as strength and muscle mass. Likewise, evidence to date suggests either no effect or negative effects of CWI on molecular mechanisms involved in regulating adaptations to resistance training. Importantly, no study has shown beneficial effects of post-exercise CWI on resistance molecular responses or training adaptations. However, caution is needed in interpreting these studies as they may not apply to all training scenarios. Nonetheless, based on the evidence to date, there seems no rationale for incorporating CWI into a resistance training programme. Whether this is true during periods of high-frequency training, with limited recovery between sessions, remains to be determined.
Original article was published 2018 on Sport Medicine, Vol. 48, issue 6.