It is likely that you have viewed videos of well-built athletes like Usain Bolt, Anthony Joshua, or Cristiano Ronaldo submerging parts of their bodies into ice-cold water. During an interview with Football Manager Carlo Ancelotti about Ronaldo's time at Real Madrid F.C., Ancelotti described Ronaldo as a self-motivated individual who frequently took 3am ice baths at the training complex, even with his former lover Irina Shayk waiting for him at home (1). Cold-water immersion has become a widely popular recovery strategy, even among elite athletes who engage in it even during the nighttime. However, if you are seeking to increase muscle mass, it is essential to consider whether immersing oneself in an ice bath can help or hinder muscle growth. Before addressing this issue, let's briefly explore the effects of cooling on the human body.
Does Cold-water Immersion Affect Muscle Protein Synthesis?
Post-exercise recovery is crucial for athletes and fitness enthusiasts. Cooling the body after exercising is a popular strategy believed to promote recovery, reducing muscle temperature and blood flow. This leads to a decrease in sensations of muscle soreness and swelling, while potentially improving exercise performance in subsequent sessions. However, recent studies have shown that the possible benefits of cooling might be due to a placebo effect, and it could even be detrimental for muscle growth.
Anabolic signaling and ribosomal biogenesis are processes crucial for stimulating muscle protein synthesis. Previous studies suggest that both of these processes are impaired following post-exercise cold-water immersion. Therefore, researchers conducted an acute and long-term experiment to determine how effective cold-water immersion is in promoting muscle protein synthesis during recovery from exercise.
The results indicated that cold-water immersion is not effective in promoting muscle protein synthesis, hindering the process instead. Cooling the body after exercising was shown to impair the anabolic signaling process, ultimately resulting in decreased muscle protein synthesis. Therefore, it may not be the most optimal recovery strategy for those looking to increase muscle mass.
In conclusion, while cooling may have benefits for some aspects of post-exercise recovery, it may not be effective in promoting muscle protein synthesis. Athletes and fitness enthusiasts should consider alternative recovery strategies to promote muscle growth and optimize post-exercise recovery.
A Single-Day Experiment on Muscle Protein Synthesis
To investigate the effect of cold water immersion on muscle protein synthesis, a study was conducted on 12 healthy young male adults with prior experience in resistance-type exercise. The participants were asked to perform a resistance-type exercise session, followed by immersion of one leg in cold water (8°C) and the other in thermoneutral water (30°C) for 20 minutes. Immediately after the water immersion, the participants were given a protein shake that contained 20 grams of intrinsically labeled milk protein.
The protein shake used in the study was "intrinsically labeled," which means that certain amino acids in the shake were specifically labeled to determine where they would end up in the body, particularly in the muscles. Tracers were also infused, and blood and muscle samples were taken for 5 hours after the post-exercise water immersion. This enabled the researchers to examine exactly what happened to the amino acids from the protein shake in the muscles and to measure the muscle protein synthesis.
The results of the study showed that the muscle protein synthesis response was impaired in the leg that was immersed in cold water compared to the leg that was immersed in thermoneutral water. This suggests that cold water immersion after resistance-type exercise may hinder muscle protein synthesis. Therefore, athletes and fitness enthusiasts should consider alternative recovery strategies that may promote muscle growth and optimize post-exercise recovery.
What we could discover with our athletes?
Our study revealed a significant difference in the incorporation of amino acids from the protein shake in the cooled (8°C) leg compared to the leg that was recovered at normal (30°C) temperature. Moreover, we observed a noticeable decrease in muscle protein synthesis in the cooled leg during the first five hours of post-exercise recovery, compared to the thermoneutral leg. These findings clearly indicate that post-exercise cold-water immersion has a negative impact on muscle protein synthesis during recovery from exercise.
To investigate whether these acute findings have any implications for long-term muscle gains, we conducted further analysis.
Experiment on Muscle Protein Synthesis over a Longer Period (2 Weeks)
We conducted a 2-week experiment with the same participants where they visited our lab for 7 resistance-type exercise sessions on non-consecutive days. After each session, we once again performed the same cold water immersion procedure where one leg was immersed in cold (8°C) water and the other leg in thermoneutral (30°C) water for 20 minutes. After the immersion, we provided a 20 g protein shake to the participants. In addition, we provided our participants with an oral tracer every day to determine muscle protein synthesis over the 2-week period.
What we could discover with our athletes at the second time?
The results of our longer-term experiment were consistent with those of the acute experiment. We once again observed a significant reduction (by 12%) in muscle protein synthesis over the entire 2-week period in the leg that was cooled after each exercise session compared to the thermoneutral leg. Therefore, we have demonstrated that the negative impact of post-exercise cold-water immersion on muscle protein synthesis extends to the longer-term.
Impact of cold-water immersion on muscle mass and strength gains
Up until now, we have focused on muscle protein synthesis, which is crucial for muscle repair and growth. However, the increase in muscle protein synthesis doesn't always lead to long-term gains in muscle mass. It's essential to examine studies that have measured muscle mass and strength gains over more extended periods. Consistent with our findings on muscle protein synthesis, well-designed previous experiments have demonstrated that post-exercise cold water immersion hinders skeletal muscle fiber hypertrophy, as well as muscle mass and strength gains.
What do we learned
Despite many athletes still performing cold-water immersion, based on well conducted experiments, we can now conclude that if the goal is to increase gains in muscle mass and strength you should avoid cold-water immersion as a strategy for post-exercise recovery.
Sources to deep dive
- Figueiredo, V. C., Roberts, L. A., Markworth, J. F., Barnett, M. P. G., Coombes, J. S., Raastad, T., … Cameron-Smith, D. (2016). Impact of resistance exercise on ribosome biogenesis is acutely regulated by post-exercise recovery strategies. *Physiological Reports*, *4* (2), e12670. doi:10.14814/phy2.12670
- Roberts, L. A., Raastad, T., Markworth, J. F., Figueiredo, V. C., Egner, I. M., Shield, A., … Peake, J. M. (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. *The Journal of Physiology*, *593* (18), 4285–4301. doi:10.1113/JP270570
- Fuchs, C. J., Kouw, I. W. K., Churchward-Venne, T. A., Smeets, J. S. J., Senden, J. M., Lichtenbelt, W. D. van M., … van Loon, L. J. C. (2020). Postexercise cooling impairs muscle protein synthesis rates in recreational athletes. *The Journal of Physiology*, *598* (4), 755–772. doi:10.1113/JP278996
- Fyfe, J. J., Broatch, J. R., Trewin, A. J., Hanson, E. D., Argus, C. K., Garnham, A. P., … Petersen, A. C. (2019). Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. *Journal of Applied Physiology (Bethesda, Md.: 1985)*, *127* (5), 1403–1418. doi:10.1152/japplphysiol.00127.2019