Research: Cold Water Immersion Stunts Muscle Hypertrophy
The thought of cold water immersion may not instantly sound appealing to the uninitiated.
Yet despite this perception, we often underrate its ability to enhance our health and quality of life.
Thanks to pioneers like Wim Hof and his Wim Hof Method, we are slowly turning this icy public perception of cold water immersion therapy into a warm friend.
Interestingly, despite the broad benefits of cold water immersion, we’re slowly starting to question its role immediately post-injury and exercise.
Whether it be the use of an ice pack, ice bath, cold shower, cold bath or the ocean, the medical and athletic communities are slowly backing away from recommending ice to treat injuries. Particularly when it may be doing the opposite of what we expect.
So I read with interest a new study from Australia looking at the effects of cold water immersion on muscle adaptation post-workout.
And it’s no surprise to see research come out questioning the use of cold post-workout. After all, rehab and recovery rely on very similar physiological processes.
It’s studies like these that continue to highlight our need to reconsider current health and fitness protocols and make sure the theory and its applications hold up.
So let’s unpack what they found.
Underrated Benefits of Cold Water Immersion Therapy
Before we get into the details of the study let’s quickly talk about the benefits of cold water immersion.
In a general sense, the body thrives with exposure to the cold. However modern convenience allows us to divorce ourselves from its presence at every opportunity.
And this type of attitude may be costing us more than we realize in regards to our health and wellness.
The following are some underrated benefits of cold water immersion:
- Better circulation: the cold is like resistance training for our vessels. The more it’s exposed to extremes in temperature the more efficient and responsive it becomes over time.
- Immunity boost: cold exposure stimulates the release of chemicals associated with a healthy immune system leaving you less vulnerable over time.
- Metabolism: the cold generates a greater percentage of brown fatty tissue in the body. This type of tissue assists with temperature regulation and increased energy production.
- Nervous system down-regulation: This often sounds counterintuitive but the cold can also help you relax. Cold water immersion stimulates your parasympathetic nervous system allowing you to ‘reset’ a heightened system associated with stress.
- Invigorate yourself: Cold water immersion can also give your mood a boost by stimulating the release of endorphins.
So with these broader benefits in mind, let’s understand the potential impact of cold water immersion on muscle adaptation post-workout.
Details of the Study
The Australian research group looked at the effects of cold water immersion on muscle adaptation after resistance training.
The detailed study and its findings were published in the Journal of Applied Physiology in November 2019.
Sixteen men aged around their early-mid twenties were selected to participate in the study. Each was selected based on a lack of regular resistance training over the previous 6 months.
Participants underwent a series of baseline tests prior to the commencement of their training program. The same tests were performed at the end for comparison.
- Bone scan (DXA – dual X-ray absorptiometry scan)
- Muscle biopsy
- 1RM leg press
- 1RM bench press
- Squat jump (peak force recorded)
- Squat jump with a 3-second pause at the bottom (peak force recorded)
- Push up with 2-second pause at the bottom (peak force recorded)
Following baseline tests, participants were paired with someone displaying comparable 1RM leg press results. Each was then randomly allocated to either the cold water immersion group or the control group.
Both groups began their resistance training program at least 72 hours after preliminary testing.
Resistance Training Program:
Each participant took part in the same resistance training program (outlined below) over the following 7 weeks.
Five minutes after each workout participants began their designated recovery protocols. The cold water immersion group sat in an inflatable bath filled with water at 10°C (50°F) for 15 minutes.
Those in the control group had the pleasure of sitting on a chair in a room for 15 minutes with the temperature set to a comfortable 23°C (74°F).
The study ultimately found cold water immersion post-resistance training “blunted muscle fiber hypertrophy”.
Interestingly, these results did not impede maximal strength gains.
Limitations of the Study
As with any study, it’s important to consider the reliability of these results. How well we can generalize them to the wider population? It’s an important question considering many are quick to take research results as gospel without considering the context in which they were obtained.
The obvious feature here is the small sample size. A study with 16 participants – all of which were males around their early 20s, may make any results hard to apply to everyone else.
Similarly, the pre-requisite for entrance into the study was a lack of resistance training in the preceding 6 months. This makes it tricky to relate to anyone well-versed in resistance training – the cohort most likely to have an interest in these results.
Furthermore, the study only tested the effects of cold water at 10°C within a 5-20 minute window post-workout. This makes it a little tricky to assume the same effects for all “cold” temperatures and timeframes. Are the effects linear? Would we expect a greater impact on muscle hypertrophy the colder the temperature gets? Is there a threshold where we finally affect maximal strength gains? How long after a resistance program does cold water immersion still have an impact? As always, we need more research to put the pieces together.
What Does All This Mean?
In isolation, it’s always hard to let one study dictate a change in your beliefs or training regime. However, the findings of this Australian study seem to fall in line with the industry’s growing apprehension towards cold exposure for immediate post-workout recovery.
As a quick side note, it’s important to distinguish this from the use of cold water immersion for other reasons. For example, an ice bath has many benefits for nervous system down-regulation, immune system strengthening, etc. However, its best used as far away from any training stimulus as possible (ie. the next morning) to avoid similar effects to those found above.
This study suggests those looking to maximize muscle hypertrophy should avoid cold water immersion immediately after resistance training. Even if muscle hypertrophy is low on your to-do list, it’s probably best practice to leave cold therapy alone.
And this isn’t to say it’s cold water immersion or nothing. Instead of cold, we need to invest our time, energy and focus towards options that better respects our physiology and it’s programming.
Whether or not this detailed Australian study is the golden bullet for cold water immersion post-resistance training remains to be seen.
However, with more and more evidence mounting against the use of cold in the early stages of recovery (and injury rehab), it may be best to consider alternative methods instead.
At the end of the day these results may not mean life or death, but if you’re taking the time to invest in your health and fitness, why not just get out of your own way?
What do these results mean to you? How does it fit within your own thinking? Let me know below!
Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. https://www.physiology.org/doi/full/10.1152/japplphysiol.00127.2019