Reader Rob pointed me to a study on how cold water immersion after a workout affects muscle growth: Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training.(1) This study has to do with full immersion, but could cold showers cut muscle growth?
First, here’s the layman’s summary of the article:
Awhile back I wrote about cold thermogenesis, and what parts of it were hype and what were reality. In short, exposure to cold water does have health benefits, but weight loss is probably not one of them.
I also mentioned my habit of taking cold showers, and that the water temperature at the time (November 1) was about 66 degrees F.
These day – end of December – the temperature of my showers is more like 56 degrees F.
When I first read the above study, I dismissed it as being of any relevance to my own practices. The study concerns *immersion* in cold water for 10 minutes. I don’t do immersion and my exposure is much less than 10 minutes, maybe 2 minutes this time of year.
The study doesn’t say how cold the water was. (At least not in the abstract, and they want money for me to read the whole paper.)
But the gains of those who immersed in cold water were cut dramatically. In the group that did not immerse themselves in cold water, “Isokinetic work (19%), type II muscle fibre cross-sectional area (17%) and the number of myonuclei per fibre (26%) increased in the ACT group (all P < 0.05)”.
In part of the study, they looked at the consequences of a single exercise bout followed by cold water immersion or not, and activation of satellite cells and muscle synthetic proteins was greater in the group that did not immerse. The study authors conclude:
These data suggest that CWI [cold water immersion] attenuates the acute changes in satellite cell numbers and activity of kinases that regulate muscle hypertrophy, which may translate to smaller long-term training gains in muscle strength and hypertrophy. The use of CWI as a regular post-exercise recovery strategy should be reconsidered.
I’m now ready to reconsider taking a cold shower after a session of weightlifting, and in fact I’ve stopped doing so.
This time of year the water is likely cold enough to cut my gains, and besides, why take the chance?
The cuts in gains in the study were far larger than I would have expected.
How does all this work? Athletes who do cold water immersion say that their exercise recovery is better. The better recovery probably comes about because the cold dampens inflammation.
The problem is, inflammation is necessary for muscle hypertrophy. Applying weights to muscles causes signals to be sent telling the muscles to grow, and inflammation is a part of these signals.
Cold showers have benefits, among them activation of the hypothalamic-pituitary axis, better immune function, and an antidepressant effect. But done post-workout, they may very well decrease muscle growth. I continue to take them daily, but not after a gym session.