Cold water immersion is a popular strategy to recover from exercise. It involves immersing the body in cold water for a few minutes after an intense workout. Many athletes and fitness enthusiasts swear by this practice, believing that it reduces muscle fatigue and soreness, and speeds up the recovery process. However, recent research suggests that regular cold water immersion may not be as beneficial as previously thought.
A study published in the Journal of Physiology compared the effects of cold water immersion and active recovery on muscle mass and strength after 12 weeks of strength training. The researchers also examined the effects of these two treatments on hypertrophy signaling pathways and satellite cell activity in skeletal muscle after acute strength exercise. The study found that cold water immersion attenuated long-term gains in muscle mass and strength. It also blunted the activation of key proteins and satellite cells in skeletal muscle up to 2 days after strength exercise.
These findings challenge the notion that cold water immersion improves recovery after exercise. Individuals who use strength training to improve athletic performance, recover from injury, or maintain their health should therefore reconsider whether to use cold water immersion as an adjuvant to their training.
The study offers new and important insights into how cold water immersion during recovery from strength exercise affects chronic training adaptations and some of the molecular mechanisms that underpin such adaptations. Cold water immersion delayed or inhibited satellite cell activity and suppressed the activation of p70S6K after acute strength exercise. These effects may have been compounded over time to diminish the expected increases in muscle mass and strength as a result of training.
Satellite cells play an important role in regulating muscle hypertrophy in response to strength exercise. By suppressing and/or delaying satellite cell activity in muscle after each training session, cold water immersion diminishes long-term gains in the numbers of myonuclei and muscle mass. The study also compared acute changes in downstream targets of the mTOR and ERK pathways, including p70S6K, 4E-BP1, and rpS6. The results of the study indicate that cold water immersion blunted p70S6K phosphorylation in type II muscle fibers, which could partly explain the observation that the cross-sectional area of type II fibers did not change after strength training and cold water immersion.
Reductions in muscle blood flow and temperature may be involved in the physiological and/or biochemical factors responsible for the lower activation of satellite cells and p70S6K after cold water immersion. By reducing muscle blood flow, cold water immersion may reduce the delivery of amino acids to skeletal muscle, and this could suppress signaling pathways that control muscle protein synthesis after exercise. Cold shock inhibits myogenin expression in myoblasts and stops them from forming myotubes. By extension, cold shock could inhibit satellite cells from differentiating and adding to the myonuclear domain. Cold shock also induces the expression of the cell cycle regulatory proteins p53 and p21 in various cell types, which play an important role (both stimulatory and inhibitory) in regulating muscle growth and remodeling.
The study has important implications for athletes, fitness enthusiasts, and practitioners working with clinical populations who often seek ancillary strategies to enhance the benefits of strength training. It suggests that cold water immersion may not be an effective post-exercise recovery modality and may actually interfere with long-term training adaptations to exercise training.
It is important to note that the study was conducted over 12 weeks of strength training and examined the effects of regular cold water immersion. Therefore, it is possible that occasional use of cold water immersion may not have the same negative effects on long-term gains in muscle mass and strength.
It is also important to consider that there may be individual differences in response to cold water immersion. Some individuals may find that cold water immersion improves their recovery and allows them to perform better during subsequent training sessions. Therefore, it is important for individuals to experiment with different post-exercise recovery modalities and find what works best for them.
In conclusion, the study suggests that regular use of cold water immersion may not be an effective post-exercise recovery modality for individuals who use strength training to improve athletic performance, recover from injury, or maintain their health. The study highlights the importance of considering individual differences in response to recovery modalities and experimenting to find what works best for each individual.