You have probably seen footage of well-built athletes such as Usain Bolt, Anthony Joshua, or Cristiano Ronaldo that have immersed (parts of) their body into ice cold water. There has
been this interesting interview with Football Manager Carlo Ancelotti about Cristiano
Ronaldo during his time at Real Madrid F.C. “…Cristiano Ronaldo, a self-motivating near-
cyborg who took 3am ice baths in the Real Madrid’s training complex. “Even though he had
Irina Shayk waiting for him at home!” Ancelotti yelps, referring to the Portuguese’s former
lover...” (1).
Given that these top athletes use cold-water immersion (even during the night), it has been
one of the most popular and frequently applied recovery strategies. However, if your aim is
to increase gains in muscle mass, how good is it then to immerse yourself in such an ice
bath? Will it help or actually hinder the capacity for muscle growth? Before answering that question let’s first look (briefly) at the impact of cooling on our body.
Impact of cooling the body
It is well-documented that cooling the body after exercise reduces both muscle temperature
and blood flow. Given these physiological changes, it has been claimed that this will improve the post-exercise recovery process. Indeed, there is evidence that cooling after exercise can decrease sensations of muscle soreness, likely because cold-induced decrements in tissue temperature lower acetylcholine production and nerve conduction velocity, which exerts an analgesic (pain reducing) effect. Furthermore, post-exercise cooling has been shown to lower muscle swelling and improve exercise performance in a subsequent exercise session (note: in some, but not all, studies). So, yes there could be reasons for athletes to cool the body after exercise. However, there is also data to suggest that cooling may not be beneficial for post-exercise recovery and/or that the possible benefits are (for a large extent) due to a placebo effect (i.e., it feels good “and works” for someone merely because that person has a belief that it works) (see discussion section of (2) for more information and references).
"Cooling may not be beneficial for post-exercise recovery and ... the possible benefits are (for a large extent) due to a placebo effect"
Although cooling may have benefits for some aspects of recovery, recent evidence has
shown that post-exercise cooling could in fact be detrimental when the aim is to build our
muscle mass. Previous work has shown that both anabolic signaling and ribosomal
biogenesis is impaired following post-exercise cold-water immersion (3, 4). Both these
processes are key for stimulating muscle protein synthesis (which is important for repairing
muscle damage and the muscle growth response). Therefore, our question was: “how good
is cold-water immersion actually when looking at the muscle protein synthesis response
during recovery from exercise?”
In order to answer this question, we decided to conduct an acute as well as longer-term
experiment (5).
Acute (single day) muscle protein synthesis experiment
We recruited 12 healthy young male adults that were familiar with resistance-type exercise.
We asked them to come to our laboratory and let them perform a resistance-type exercise
session followed by one leg that was immersed (for 20 minutes) into cold water (8°C) and
the other leg into thermoneutral water (30°C). Immediately after water immersion we also
gave 20 grams of an intrinsically labeled (milk) protein shake. This “intrinsically labeled”
means that we had some amino acids within that protein shake “specifically labeled” so we
could see exactly where those amino acids would end up in the body and, particularly, in the muscles. Together with an infusion with tracers and taking blood and muscle samples for 5 hours after post-exercise water immersion, we could then exactly see what happened to the amino acids from the protein shake into our muscles and what happened to muscle protein synthesis.
What did we find?
When looking at what happened to the amino acids from the protein shake, we observed
that substantially less of these amino acids were being incorporated into the leg muscle that
was cooled (8°C) compared to the leg that recovered at the normal (30°C) temperature.
In addition, we also observed a clear impairment in post-exercise muscle protein synthesis in the cooled leg, compared to the thermoneutral leg (30°C) over the first 5 hours of post-exercise recovery. Therefore, this clearly shows a negative effect of post-exercise cold-water immersion on muscle protein synthesis during recovery from exercise.
As most people are obviously mostly interested in seeing whether their long-term gains
would be impacted (or not) by cooling as a recovery strategy, we also wanted to know
whether these acute findings would translate into longer-term findings.
Longer-term (2-week) muscle protein synthesis experiment
We also applied a 2-week experiment, where we asked the same individuals to come to our
lab during a 2-week period to perform 7 exercise sessions (on non-consecutive days) after
which we again performed the same cold water immersion procedure (20 min of one leg in
cold (8°C) and one leg in thermoneutral (30°C) water). Subsequently, we also provided a 20
g protein shake after every session. By providing our participants every day with an oral
tracer, we could determine muscle protein synthesis over the 2-week period.
What did we find?
We observed similar findings as in our acute experiment, as we again found that muscle
protein synthesis was substantially lower (by 12%) over the full 2-week period in the leg that
was cooled after every exercise session compared to the thermoneutral leg. So, we showed
indeed that the acute (negative) effects of post-exercise cold-water immersion translate
into the longer-term.
Cold-water immersion and gains in muscle mass and strength
So far, we have been talking about muscle protein synthesis, which is (as I mentioned) an
important process for repairing muscle damage and the muscle growth response. However,
albeit being an important component, increases in muscle protein synthesis do not
necessarily reflect gains in muscle mass over a long-term period. Therefore, it is also
important to look at studies that actually measured gains in muscle mass (and strength)
over even more prolonged periods. In line with our muscle protein synthesis findings,
previous well conducted experiments have indeed shown that post-exercise cold water
immersion also attenuates skeletal muscle fiber hypertrophy (6), as well as gains in muscle
mass and strength (4).
Conclusion
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.
Access our 'Ice bath or hot bath for athletes? webinar recording through this link.
Reference
https://www.ft.com/content/720cae92-1c32-11e6-a7bc-ee846770ec15?siteedition=intl
Thesis Cas Fuchs “Strategies for Post-Exercise Recovery”: https://cris.maastrichtuniversity.nl/en/publications/strategies-for-post-exercise-recovery
Figueiredo VC, Roberts LA, Markworth JF, Barnett MP, Coombes JS, Raastad T, et al. Impact of resistance exercise on ribosome biogenesis is acutely regulated by post- exercise recovery strategies. Physiol Rep. 2016;4(2)
Roberts LA, Raastad T, Markworth JF, Figueiredo VC, Egner IM, Shield A, et al. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. J Physiol. 2015;593(18):4285-301
Fuchs CJ, Kouw IWK, Churchward-Venne TA, Smeets JSJ, Senden JM, Lichtenbelt W, et al. Postexercise cooling impairs muscle protein synthesis rates in recreational athletes. J Physiol. 2020;598(4):755-72
Fyfe JJ, Broatch JR, Trewin AJ, Hanson ED, Argus CK, Garnham AP, et al. Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. J Appl Physiol (1985). 2019;127(5):1403-18
