Why Icing For Injuries Is Killing Your Recovery

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Quick points

• While icing may have a place in comfort, its benefits have been consistently demonstrated to be less than effective in the healing process.

• As you can imagine, cold slows down repairing mechanisms. Think of a cryogenic freeze as an extreme example. The purpose is to decelerate biochemical reactions in the cells.

• What can you do instead? Use ice only initially if a drastic amount of swelling occurs. NSAIDs and creams can be used to dampen residual pain, while movement and traction are a must.

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When it comes to icing, I find it funny and slightly appalling how prevalent its use, even by physical therapists, is to this day. Ice is great; it makes something sore feel good (temporarily) and makes your drinks nice and cold! But that’s about where it really ends. At least for our context in sports, ice doesn’t play the kind of helpful role we were led to believe 40 years ago when it first rose to prominence. 

Repair mechanisms

Allow me to get only slightly technical for one second so we can better understand what mechanisms occur when tissue is damaged that prompt healing.

When you roll an ankle, cut your skin, break a bone, pull a muscle, or overstretch a tendon, you elicit a reaction from your immune system to rush several types of cells and chemicals to the site of the injury. Regeneration begins.

Depending on the type and severity of the injury, this could start with immediate vasoconstriction (blood vessels narrow) and blood clotting to stop any bleeding and any bad stuff entering an open wound. But the next part is always involved, and that is inflammation.

When you see your skin get red after a bout of “pressure”, your blood vessels vasodilate (widen up) to allow for white blood cells (neutrophils and macrophages) to enter the area and move around freely.  The white blood cells eat up all the bacteria that may have entered the body (phagocytosis) and release the hormone IGF-1, then fibroblast cells proliferate (multiply) and begin to heal the problem area. 

Photo: Quick visual representation of the inflammatory response to injury [RHSHealthScience]

Phew! That may seem informationally dense for some, but it’s a relatively straightforward and short-stepped process compared to many others in your miraculous body. To learn even more, check out our in-depth article on plantar fasciitis.

Why the hate on ice?

All that said, if inflammation is key to healing, would intentionally slowing it down be a logically sound investment? Probably not. Outside of what most sports blogs on the internet will reconstitute, you will be hard-pressed to find much support for its implementation for exercise-induced muscle damage (EIMD) in the scientific community.

Ice slows down swelling which in turn slows the healing process, thus hampering your own recovery. It absolutely helps numb the pain and will help keep initial swelling from getting out of control; too much swelling may likewise slow down healing or lead to more swelling and lack of range of motion. I would exercise caution as to how often you use ice, and when. More on this later.

This also includes other forms of cryotherapy, such as ice water immersion. I’m sorry to say it to all the hardcore ice bathers and whatnot (I was there at one point in my career as well), but there’s just no real conclusive evidence it does much outside of temporary relief either. There’s some evidence to support improved oxygen and nutrient perfusion. There’s also plenty of anecdotal evidence for dulled pain sensations and alertness as one would expect given vasoconstriction, reduced muscle temperature, the adrenaline spike from “cold shock”, etc.

If the goal is muscle power recovery or repair as an elite-level athlete, it’s not solidly proven to do you much justice. In some extreme instances, it can be quite dangerous. We’ll go more into post-workout pains and how to treat them when we get to other myths and legends posts, including DOMS.

Even Dr. Gabe Mirkin, the man who coined the RICE technique in the 70s, came out years ago to rebuff the efficacy of icing injuries and supported other studies that proved its inefficiencies. A real man understands that things change and he can be wrong every once in a while, so props to a true man of science. “Nobody believes in rest anymore,” he says, and “there is no data to show that ice does anything more than block pain.” 

“And there is data that shows it delays healing.” 

“RICE is just something that stuck—and it’s wrong,” Mirkin adds. “I’m partially responsible for this misinformation.”

Additional problems with icing

Much like one of the following studies states, I find there are many examinations that review healthy test subjects. Herein lies a flaw in the data. While it may be possible to assume or postulate data based on healthy individuals, it doesn’t directly correlate to real-world injuries and the effects the tests set out to establish. In other words, if you’re going to do an experiment to determine if topical cooling has a positive healing correspondence with injured tissue, use injured tissue.

More often than not, research is done on the effect of icing on muscle soreness, and after bouts of eccentric loading. That’s not to say there aren’t those out there that do focus on athletes with pre-existing sports-related injuries. Some are referenced in this article.

There are, though, many studies done on animals that show some promising data to back the legitimacy of ice on tissue healing, but there is almost no associative evidence for its efficacy on humans. A good number of those studies are also performed on rats, which have a stark difference in muscle size to humans. The largest problem, we think, has to do with how much adipose (fat) tissue is contained in the area being tested, and how deep the tissue in question is. You can reason that, if your skin and fat act as a thermal barrier to any underlying tissues, it would take a longer time for the cold to penetrate them and colder temperatures to lower the tissue to a point it is influenced.

You might say, “OK bro, if that’s the case then just make it a little colder or keep it on there for longer.” Fair point my friend. There are just a few problems with that in practice. In animal studies, we’re able to produce some muscle tissue temperatures of around 10°C (50°F). The majority of studies on humans though have demonstrated how difficult it is to reduce human muscle tissue below 25°C (77°F) and that’s after 50 minutes of treatment [6]. The same study references another that was able to achieve 21°C (69.8°F) after 20 minutes using crushed ice [8]. The caveat? It was at a depth of only 1cm and on a test subject with “very low levels of adipose tissue thickness.”

For every 1cm increase in depth, the cooling rate drops from 0.72°C/min to 0.45°C/min. An easier way to think about this is that for just one extra centimeter of thickness, the rate of cooling needed to penetrate is 37.5% worse. This equates to an additional 7.5 minutes of extra icing time minimum to get the above case study to 21°C if they had a little more fat. What’s worse, that may not even come close to cooling deeper tissue injuries. So you can continue to push the temperature and time, but if you can’t reach the muscle that’s damaged, it’s a null attempt and might only add to the risk of secondary injury.

Why is this important? Is there an ideal temperature where we think there’s a positive effect on muscle repair? Do we see ANY effectiveness when cooling tissue currently?

In short, we don’t know. There’s some evidence that points to optimal levels of cooling between 5-15°C which theorizes a decrease in metabolic rate and limits secondary injury, but it’s just theory. Even then we aren’t fully certain it will benefit in any way.

Photo: What you might look like to get “cold enough“ to reach optimal affected area.

The colder you get, and for longer times, the more likely you are to run into those secondary injuries, such as ischemia. This is where you begin restricting blood flow to tissue (due to vasoconstriction brought on by the cold in this context), which in turn deprives oxygen to the tissue causing a potential for negative, irreparable tissue damage. It worsens if you also add in external blood flow restrictions like wrapping the area. Nutrients cannot rush in to help, and waste cannot be removed during this time. No bueno.

Depending on the specific method of application used (ice pack, a bag of ice, ice bath, gel packs, etc), the heat your skin gives off can raise the temperature of the applicant, thus depreciating its potency. Interestingly, that same heat your skin gives off creates a phase change (solid to liquid) in ice-based modalities and the resultant water can wick away some more heat from the area actually keeping it cooler [7]. Again, this was only significant at a depth of 1cm.

It should be mentioned we don’t think you should fear more extreme ischaemic conditions under most situations. Unless you are cutting off blood flow or cooling to some extreme that is likely more difficult to achieve under normal circumstances, you should be fine. As an athlete, if you are sitting around with a tight ice wrap on for longer than 10-15 minutes, the area is tingling due to blood flow restriction, or you are wincing through pain, you should stop (lol).

Many people fall trap to the American ideology of “No pain, no gain” or “The more, the better.” These are unfortunately quite silly if you are putting yourself at more risk of long-term injury. Change occurs slowly. No matter how many pushups you do today, it is not going to make you bigger tomorrow. It may ruin you for a week if you do too many, though.

Animal dichotomy

The more you read into modern data on icing, the more polarizing the results are between studies performed on humans as well as animals. Here are a few examples, highlighted by some glaring points of contention.

Schaster et al. [9] caused a closed muscle injury via an impact (crush injury) to the left extensor digitorum longus muscle of a rat — a guy dropped a controlled weighted ball on a rat’s thigh. As a treatment, the leg was cooled for 6 hours to achieve a muscle surface temperature of 8°C.

The study found that within 24 hours the intramuscular (within the muscle) pressure was significantly reduced compared to the control group, as one would expect when you reduce swelling. The authors noted other benefits such as diminished tissue damage and myonecrosis (death of muscle fibers), as well as a renewal of weakened capillary density [9, 10]. By refreshing capillary density surrounding the muscle fibers, you improve the delivery of oxygen and nutrients to your muscles and in turn, allows you to clear waste products faster. This could actually be quite beneficial for endurance athletes after a particularly intense workout, so perhaps the ice bath is an interesting option after all for recovery purposes…but wait, there’s more.

The early slowing of muscle decay and leukocyte [white blood cell] infiltration in the cooled muscles “may in part be due to a temperature-induced reduction in calcium activation of calpain activity, which results in a reduction in calpain-induced muscle degeneration.” [4, 24] This was mirrored in a late 2019/early 2020 study by Fuchs et al. [16] that aimed to determine the effect of cooling on protein synthesis. Spoiler alert - post-exercise cooling impairs it.

FYI Calpain is a major intracellular protease. All that really means is it’s an enzyme inside your cells that breaks down proteins into amino acids, which we know are the building blocks of muscle. They also have a hand in regulating important processes elsewhere in the body such as blood clotting, programmed cell death, bone formation, immune function, and more.

These same studies [9, 10] demonstrate that the cutback in leukocyte diffusion led to a weakening of muscle proteins IGF-1 and TGF-β1, used in wound healing mechanisms such as satellite cell activation.

Because of this, repair and recovery from crush damage in muscles were significantly delayed. “The cryotherapy-treated muscles, collagen deposition or scarring was significantly more extensive at 14 and 28 days post-injury relative to the untreated muscles.” [4]

In other words, post-injury cryotherapy not only slowed down recovery and repair but also resulted in thicker collagen deposits. So while there were some positive results short-term, the long-term effects were still negative in regard to healing injury.

The problem we have with animal studies is the same we have all had for decades. While studies performed on animals can be indicative of what may occur within the human populace, they do not always parallel. We can’t necessarily write them off, nor can we definitively say they will work the same. Unfortunately, without more positive data on human subjects, it remains only a slight ray of hope for the cooling campaign.

One issue with the rat study above is the transparent size difference between rat muscles and human muscle. If you were to assume we needed to achieve similar temperatures for optimal success, you would have to exponentially increase time/temperature which would assuredly do more damage than good. It was performed for 6 hours as it were for the rat. Specifically, the study is also aimed at the effects of cooling on compressive “crush” injuries.

This is a limited experience injury for most athletes outside of full-contact sports. We are more likely to suffer from tension or torsion-related injuries such as pulls, strains, and twists of the soft tissues and joints. Though, many of the same findings were made in other studies with more serious eccentric-induced damaged tissue [2]. They found topical cooling caused a decrease of TNF-α (tumor necrosis factor-alpha) and IL-6 (interleukin-6) in the release of inflammatory cytokines after eccentric muscle damage, which corresponds to the hindering of the healing process by slowing cell turnover.

NSAIDS

Instead of icing those basic nagging injuries, one could recommend other options for the pain, for starters. Painkillers are a popular alternative along with numbing creams.  Drugs like Advil, Aleve, Motrin, and Ibuprofen are good at covering up pain signals but they are also used to specifically inhibit inflammation. It’s in the name of the drugs — non-steroidal anti-inflammatory drugs, or NSAIDs. I would generally urge against using them in most cases.

There’s some research that shows extensive NSAID usage can suppress satellite cell proliferation and differentiation, thus growth/regrowth. Those little satellite cells are stem cells that surround your tissues and wait for damage to occur to take action in becoming what they need to be to heal and repair. For an athlete, in a high-level speed and power athlete, in particular, this is something we want to mediate as much as possible.

The research is sparse in this area so I wouldn’t worry too much about NSAIDs affecting this aspect, but remember that pain can also be a good thing. It allows feedback to your system that tells you there is something wrong there, and the signaling is precisely what helps your bodyguard against further damage. When you ice or use NSAIDs, you tend to take the problem and mask it so you can go about doing the same exact thing that got you injured, creating more problems and longer recoveries.

If pain is the problem and it’s affecting your work or daily routine, I would suggest Acetaminophen, such as Tylenol, as an alternative. We’ve all heard of or used it, and it’s easily accessible. The best part is it targets pain only and eschews blocking inflammation.

Photo: NSAIDs merely mask protective signals and deter healing mechanisms in your body [purathrive.com]

What to do instead

Cryotherapy, or topical icing as being currently discussed, will not likely be successful in cooling muscle sufficiently to have any significant influence on muscle repair, regardless of the degree of injury. In fact, for most exercise-induced injury for all you athletes out there, it’s likely to do more harm than good outside of a mood or energy-inducing effect, of which there is plenty of merits.

There are many other options that have been assessed or used in spheres anecdotally for some time. Some of those include angiotensin II receptor blockers, platelet-rich plasma (PRP) treatments, glucocorticoids, fenoterol, insulin-like growth factor-1 (IGF-1), decorin, curcumin and suramin, hyperbaric oxygen, massage, and ultrasound to name a few [11]. Many listed are designed to curb inflammation, help widen your blood vessels, or coax a growth response.

Of these, several have the potential to be worth a try or look into, while others have far too little evidence to warrant. If we were to suggest any, we would look into curcumin, suramin, and hyperbaric oxygen chambers. Each has its limitations and will depend on the severity of the injury. Others such as glucocorticoids and PRP shots have shown promise, but they can be expensive and tend to have some large downsides. The others have far too little proof of potency to spend your time on. We’ve tested many over the years on ourselves and athletes with little to no concrete benefit.

You may be thinking that massage would be a good choice. After all, professional athletes use massage therapists before and after workouts all the time. It is not that costly to try in most senses. That may be true, but professional athletes also tend to do anything they think is going to help them succeed without a slew of scientific evidence. Like everyone else, if most people are doing it or it’s an available option, why wouldn’t you give it a shot? Let’s remind ourselves, massage, like icing, feels good. That’s enough to justify just about anything for all of us.

Torres et al. [12] reviewed numerous studies overviewing several different modalities only to conclude that, while massage showed the most beneficial effect on muscle soreness, it had little to no effect on muscle force recovery or repair following eccentric exercise up to 72 hours after exercise. Many studies have concluded the same [13, 14, 15]. Where massage may shine, is in its ability to not only relax, but also help reduce scar tissue or assist in manually realigning pre-existing scar tissue. Again, it’s important to remember the basis of this article is not to aid in muscle soreness, but instead expedite physical healing in the muscle.

The most effective way of getting back on your feet, so to speak, is well...getting back on your feet. Get back to moving as soon as you can with relative comfort to reteach the muscles, ligaments, tendons, joints, etc, how they naturally move.  Likely this isn’t the elegant solution or pill popper you were looking for. But often, we as humans overemphasize that which needs to be done to perform. Part of returning function is getting that swelling out, and the best way to do so is through gentle traction and movement, engaging your lymphatic system. What it also does, is allows for damaged tissues to be rebuilt properly via orderly fiber layout and move in the naturally used orientation.

Photo: Collagen remodeling and reorganization [Institute for Complex Molecular Systems]

A study done on rats [11] concluded that rats that went back to mobility exercises earlier, appeared to benefit significantly over those that did not.

So tie up an athletic band to a post and gently use it to take your sore arm through the motions, or your ankle, or do some light back bridges for your hamstrings. One of the worst things you can do is hop on the crutches or get in the boot and not use the injured part. 

Should we ditch RICE?

Recent studies [3] have suggested a new acronym to replace the outdated RICE; albeit hokey and absurdly lengthy. PEACE and LOVE. As if to beckon the ideology of the 1960s hippie movement, it conjures relaxed, feel-good thoughts. That said, the premise for which it stands is precisely the same as that which resides in this article.

Photo: New suggested acronym for rehabilitation that does not include icing procedures.

When might you employ ice?

We’ve discussed in length the notion that using topical cooling solutions for exercise-induced muscle damage is a less than ideal solution for recovery or training. That said, there are some interesting usages for cooling you may find of use.

While some of the following are still inadequately researched, some studies have shown some promise. Here are a few to mull over while you resent us for stomping on one of the most used after-practice rituals.

• Postoperative ice treatment has been shown to reduce hospital stays and narcotic usage due to the numbing capabilities of cold, and less blood loss. It may also slow the rate of metabolism in cells, helping to lessen secondary injury in high-risk cells. Alternatively, in just as many other studies it seems, the science community has outlined instances of no change, reduced nerve conductivity, nerve damage, “wound complications” similar to frostbite, extended vasoconstriction after ice removal, etc [23]. The jury is still out as you might expect by now.

• It has demonstrated some potential in shortening delayed onset muscle syndrome (DOMS) in submerging solutions [22]. It is also seen as a method of rejuvenating the mind for those who cannot bring themselves to sit around idly after hard workouts even if they realize there may be no benefit (no effect on peak VO2, power output, sleep patterns, basal adrenaline/noradrenaline/cortisol concentrations) [21]. Ice baths have been used more and more as methods of recovery and NOT for up-regulating repair mechanisms. This is why you might see someone like the Nike Oregon Project utilizing an ice bath between championship rounds but never after hard workouts where the goal is to let the body adapt to the stressors on its own [19].

• Thermoregulatory responses during repeat sprints or high heat environments utilizing ice slurry drinks during breaks. Essentially, sipping from ice-dominated water mixtures in between sets to keep your core temperature in check during high intensity or hot days. This method was most recently updated and researched as of May 2020 [20].

• To allude back to the beginning of the article, ice may do the best job at keeping our food and drinks cold. That said, we understand that taking a cold shower, for example, may benefit your overall health by adding sudden biological stress to the body. Our bodies adapt best when they have a bit of perceived adversity. There are studies out there in regard to telomere lengths, gene scrubbing, etc. Much like intermittent fasting or caloric restrictions on your body, cryotherapy might help to increase mood, energy, and overall health. In other words, benefits in areas outside of muscle growth. Other potential adaptations include converting white fat to brown fat, which is a much more recent discovery and there’s a lot to unpack there in the future.

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Relevant studies:

[1] http://bjsm.bmj.com/content/46/4/296.abstract

[2] http://journals.lww.com/nsca-jscr/Abstract/2013/05000/Topical_Cooling__Icing__Delays_Recovery_From.24.aspx

[3] https://blogs.bmj.com/bjsm/2019/04/26/soft-tissue-injuries-simply-need-peace-love/

[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596174/

[5] https://www.macleans.ca/society/the-end-of-the-ice-age/

[6] https://bjsm.bmj.com/content/46/4/296.long

[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC155508/

[8] Myrer WJ, Myrer KA, Measom GJ, et al. Muscle Temperature Is Affected by Overlying Adipose When Cryotherapy Is Administered. J Athl Train 2001;36:32–6.

[9] Schaster KD, Disch AC, Stover JF, Lauffer A, Bail HJ, Mittlmeier T. Prolonged superficial local cryotherapy attenuates microcirculatory impairment, regional inflammation, and muscle necrosis after closed soft tissue injury in rats. Am J Sports Med. 2007;35:93–102. doi: 10.1177/0363546506294569

[10] Bleakley CM, Glasgow P, Webb MJ. Cooling an acute muscle injury: can basic scientific theory translate into the clinical setting? Br J Sports Med. 2012;46:296–298. doi: 10.1136/bjsm.2011.086116.

[11] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899907/

[12] Torres R, Riberio F, Duarte JA, Cabri JMH. Evidence of the physiotherapeutic interventions used currently after exercise-induced muscle damage: systematic review and meta-analysis. Phys Ther Sports. 2011;13:101–114. doi: 10.1016/j.ptsp.2011.07.005

[13] Weerapong P, Hume PA, Kolt GS. The mechanisms of massage and effects on performance, muscle recovery and injury prevention. Sports Med. 2005;35:235–256. doi: 10.2165/00007256-200535030-00004

[14] Zainuddin Z, Newton M, Sacco P, Nosaka K. Effects of massage on delayed-onset muscle soreness, swelling and recovery of muscle function. J Athl Train. 2005;40:174–180.

[15] Tiidus PM. Massage Therapy in Tiidus PM ed. Skeletal muscle damage and repair. Human Kinetics Pub. Champaign IL. 2007 pp. 195–202

[16] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7028023/

[17] https://journals.physiology.org/doi/full/10.1152/japplphysiol.01187.2010

[18]

[19] https://www.runnersworld.com/advanced/a20796842/cant-hurry-love/

[20] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205515/

[21] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6700067/

[22] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7027844/

[23] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6739721/

[24] Takagi R., Fujita N., Arakawa T., Kawada S., Ishii N., Miki A. (2011). Influence of icing on muscle regeneration after crush injury to skeletal muscles in rats. J. Appl. Physiol. 110, 382–388.