In this short blog, we’ll briefly discuss cryotherapy and the misconceptions around it.
Cryotherapy is a basic equation of sports sciences and medicine. For generations, it’s been the go-to modality for post-injury management (especially sport-related musculoskeletal injury). Any bruise or twist is often initially managed by applying ice over and near the injured area.
None of this is by chance, historically there’s been good literature to show that icing an injury is a good choice. But how does practice reach such unanimous agreement and compliance, and what does ‘good literature’ mean in this context?
Firstly, let’s get the definition straight- Cryotherapy is principally the use of cold/reduction in tissue temperature for injury management, now this means that cold application could be made in any manner like using cold showers/baths/dips, ice, sprays, mild refrigeration using specialized equipment and some other phase change materials.
The use case for cryotherapy in painful conditions, musculoskeletal rehabilitation, and sports and our understanding of it throughout the years is why I am writing (and you are reading) this.
The image above illustrates the conventional understanding of “injury” in people who engage in physical activities.
To simplify, let us consider injury as a biphasic occurrence, wherein phase 1 is whatever happens that precipitates an injury; during the injuring process, and phase 2 is whatever happens afterwards (but before actual healing).
Phase 1 would then be all mechanical stresses, metabolic stresses, temperature increase, reactive oxygen species activity, and any direct trauma during physical exercise, leading to tissue damage. Here the utility of cryotherapy is pretty limited, simply because one can’t mess with the unexpected before it is evident.
Phase 2 is where all the mysteries and information lie (misinformation included). It is the point immediately after the injury event, where all the reparative processes begin (the inflammation, proliferation, reorganization of tissue structure, and return to near normal).
Historically, the literature has led us to a point where this phase is the best use case for cryotherapy and almost all clinical and non-clinical practitioners agree to it to date (at least the majority of them). The basic idea again was (still is) to mitigate secondary damage and enhance the repair process, not just post-injury but post-exercise as well [Good ol’ ICE-RICE-PRICE].
Coming back to what I mean when I wrote “good literature” in the beginning, is that there exists a timeframe within which a fact can become a phenomenon provided that there is “credible-ish” evidence to support it, and this time conveniently precedes (obviously!) the time when contradictory evidence starts to emerge. So, whatever opposing comes out against the “newly established phenomenon” is disregarded just because the fancy of it is already acknowledged by people. This initial literature before skepticism begins is what I call “good literature” (not good for all but for making a point). Now consider this and cryotherapy together and you’ll get what I mean.
So, a good amount of evidence exists in support of cryotherapy? Maybe. But there are 2 things to consider:
Much of it is based on animal studies. (say for example- skin temperature lowered post icing in a rabbit or a rat would be way different than a human, because of different adiposity, tissue layer composition, insulation, response to cold, local superficial circulation, etc.
The ‘good amount’ of evidence in support is adequately opposed by a fair amount of contradicting and (respectively) better-quality studies.
A lot of misconceptions and myths arise out of the fact that cryotherapy is a hugely popular modality (especially in sports and MSK injuries), practically the status quo of acute injury management. Clinicians aren’t too keen on reconsidering a good friend because of some “new developments”.
Let’s take a look at some of these common misconceptions about cryotherapy in general:
“Cryotherapy should be applied over the subsequent days following injury or exercise” It is a widely held belief that once a person injures a part of their body, one should ice it for a couple of days, the reason? ... “Just because”. In reality, cryotherapy should be used as close to the injury time as possible, i.e. immediately after the injury and continued up to the following 12-24 hours.
“Cryotherapy is used to reduce inflammation and tissue metabolism” Theoretically, the idea that cryotherapy aims to reduce the local tissue temperature thus slowing down the metabolic process and resulting in reduced inflammation/ local tissue metabolism sounds quite sound, but nothing of this sort has been conclusively proven in humans as of yet.
“The effectiveness of cryotherapy as a recovery modality is primarily dependent upon its ability to reduce blood flow” This is simply based on the assumption that all cryotherapy reduces tissue temperature enough to cool the vessels and slow down the blood flow. Skin temperature reduction poorly reflects deeper tissue temperature changes, so what matters more in the end is how long can you cool a tissue without discomfort (increasing the chances of cooling the deeper tissue) i.e. Total cooling time and how you achieve it.
“Icing after injury inhibits the naturally occurring repair response” Again, it’s based on the assumptions that the effects of cooling on human and animal models are alike and that extreme cooling at deeper tissues can be achieved reliably in humans as well (None of this is proven in human models).
“Ice immersion is a recommended post-exercise recovery modality” Ice water immersion or CWI (cold water immersion) is not a recommended recovery modality, as it can affect anabolic activity. But it can be reliably used as a within-session/between-exercise recovery tool.
In conclusion:
If you want to reduce pain intensity and soreness after injury go for an ice pack.
Aim to apply the ice for as long as you can (In terms of duration after injury, not days following).
Try not to regularly use ice as a recovery modality as it can adversely affect training adaptations.
You can use icing as a half-time recovery modality.
Try to stray away from using fancy ice therapies and being too sure.
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