This is an excerpt from Science and Development of Muscle Hypertrophy-2nd Edition by Brad Schoenfeld.
Proper recovery from training is considered essential to optimizing muscle gains. Various passive techniques have been advocated to enhance the post-exercise recovery process and restore the body to its normal physiological and psychological state. Cold-water immersion is one of the most commonly used modalities in this regard. The technique involves immersing all or part of the body in cold water (figure 5.1). The specific protocols vary, but prescriptions generally include water temperatures cooler than 15 °C (59 °F), with immersion durations of at least 10 minutes (12).
Figure 5.1 An athlete in cold-water immersion.
Al Powers/Zuffa LLC/Zuffa LLC via Getty Images
The findings of several systematic reviews and meta-analyses indicate that cold-water immersion helps to attenuate delayed-onset muscle soreness (DOMS) (8, 9, 46). Given that DOMS may impede lifting performance, the use of cold-water immersion seems to be of potential benefit for those involved in intensive resistance training programs. However, despite its potential recovery-related benefits, emerging evidence indicates that cold-water immersion may be detrimental to muscle development.
Acute research shows that cold-water immersion impairs intracellular anabolic signaling, and an attenuated p70S6K phosphorylation response is seen over the course of a 48-hour recovery period after resistance training compared to an active recovery period (72). The same study also showed cold-water immersion mitigated the number of Pax7+ cells and NCAM+ cells at 24 and 48 hours after resistance exercise, indicating a deleterious effect on the satellite cell response to resistance training as well. Other research shows cold-water immersion suppresses ribosome biogenesis (21), which is thought to be a key player in the long-term regulation of muscle growth (22).
The negative acute effects on anabolism seen with cold-water immersion align with findings of longitudinal research on hypertrophic outcomes. Roberts and colleagues (72) investigated the impact of cold-water immersion versus active recovery during a 12-week resistance training program. Twenty-four physically active young men were randomly assigned to one of the two recovery conditions. Cold-water immersion was initiated within 5 minutes post-exercise and involved sitting waist deep in water approximately 10 °C (50 °F) in an inflatable bath for 10 minutes. Those in the active recovery group cycled on an ergometer at a self-selected low intensity for 10 minutes. Results demonstrated a blunting of both whole-muscle hypertrophy and histological measures of Type II fiber cross-sectional area with the use of cold-water immersion. Similar findings were observed by Yamane and colleagues (90), who compared muscular adaptations between cold-water immersion and passive rest following a 6-week resistance training program of the wrist flexor muscles. Cold-water immersion treatment consisted of immersing the trained arms in a water bath within 3 minutes post-exercise. Water temperature was maintained at 10 °C (50 °F), with immersion lasting for 20 minutes. Results showed that both groups increased thickness of the wrist flexors, but hypertrophy was significantly greater in the passive recovery condition.
The underlying mechanisms by which cold-water immersion impedes anabolism remain unclear. Given that the acute inflammatory response to resistance training is implicated in anabolic signaling (75), and given that cold-water immersion alleviates symptoms of DOMS, which is associated with induction of acute inflammation, it would be logical to speculate that the anti-inflammatory effects induced by cold-water immersion play a mechanistic role. However, research on the topic is somewhat contradictory. Peake and colleagues (67) found that cold-water immersion did not alter post-exercise levels of proinflammatory cytokines and neurotrophins, or intramuscular translocation of heat shock proteins compared to active recovery following resistance training. Alternatively, Pournot and colleagues (68) reported a diminished inflammatory response when cold-water immersion was applied pursuant to an endurance exercise bout.
It can be hypothesized that negative anabolic effects of cold-water immersion are in some way related to a reduction in blood flow (50, 54), possibly by compromising post-exercise amino acid delivery to muscle (29). Exposure to cold temperatures also has been shown to interfere with anabolic signaling, potentially via an upregulation of AMPK, a known inhibitor of mTOR (12). Because research is limited, it is difficult to draw strong inferences on the topic.
In summary, current evidence contraindicates the use of cold-water immersion for those seeking to maximize muscular development, at least when used regularly. Any benefits to recovery seem to be outweighed by an impaired anabolic response to resistance training. Post-exercise heat therapy represents a promising strategy for enhancing recovery without interfering with hypertrophic outcomes and possibly even improving subsequent strength-related performance (13). Evidence shows that heat therapy, applied 2 hours daily over 10 days of immobilization, can attenuate skeletal muscle atrophy (38). Although this finding indicates potential anabolic effects, results cannot be extrapolated to benefits during performance of muscle-building protocols. Another study demonstrated that topical application of heat via a heat- and steam-generating sheet for 8 hours per day for 4 days a week significantly increased quadriceps hypertrophy over a 10-week treatment period (34). Research into this modality is preliminary and warrants further study.