Cryotherapy (from Ancient Greek κρύος meaning "icy cold, chill, or frost") is a recovery method that some pro athletes and biohackers use nearly every day. The benefits touted by cold exposure enthusiasts include faster recovery time, an enhanced immune system, increased cell longevity, decreased levels of inflammatory molecules (like interleukin 6), and, of course, an increased tolerance for exercising outdoors in the winter, especially north of the 49th parallel.
Aside from slapping an ice pack on a sore ankle after a misstep during a morning trail run, the majority of the population has never dunked themselves into a 20-minute ice bath or a hot-cold contrast shower, or stepped into a sci-fi looking cryotherapy chamber. Are they missing out on something amazing? Are you? Let’s take a look.
Does Cold Help with Pain?
A bunch of studies have come out recently that show the effectiveness of cold thermogenesis, icing, and cold water immersion. Let’s examine two of them. Both these studies looked at the effects of cold on decreasing muscle soreness, exercise-induced muscle damage, and inflammation.
The first study called The Effects of Multiple Daily Applications of Ice to the Hamstrings on Biochemical Measures, Signs, and Symptoms Associated With Exercise-Induced Muscle Damage, demonstrated that icing three times a day for 20 minutes at a time can assist with soreness. This is good news for anyone who has just started a workout program that has been leaving them feeling beat up and sore—but let’s put a pin in this notion for now. You may want to wait until you have read this entire article before you finish your squats and immediately slap on an ice pack.
In the second study, Acute Response to Hydrotherapy After a Simulated Game of Rugby, researchers found that rugby players who used two 5-minute cold water immersion sessions (ice baths) were able to significantly reduce soreness and the effects of muscle damage.
So, yes! Whether it is a cold shower, an ice bath, or some cold packs, you can break out the cold if you want to alleviate sore muscles.
Does Ice Help with Healing?
The Greek physician Hippocrates wrote about using cold therapy to control pain and swelling way back in the fourth century B.C., and the Roman physician Galen described using cold compresses for pain management on soft tissue injuries back in the first century A.D. Despite the long history of using ice for pain control, there are studies that are commonly cited in the argument against icing for healing.
If inflammation is the body’s natural way to heal an injury, why the heck would you want to stop this helpful inflammatory process?
When an injury occurs, your body creates inflammation as part of the natural healing response. So, the argument goes, if inflammation is the body’s natural way to heal an injury, why the heck would you want to arrest this helpful inflammatory process?
It has also been pointed out that icing has been shown to increase the permeability of lymphatic vessels (the tubes inside you that help carry excess fluids back into your cardiovascular system). The problem with that is, once this lymphatic permeability has been increased, there may be a risk of large amounts of fluid flowing back into the sore area. This could, in turn, cause even more swelling than before.
A study commonly cited that supports this argument is The Use of Cryotherapy in Sports Injuries, in which researchers conclude that “cold can inhibit inflammation as well as enhance inflammation.”
Also when ligament injuries were induced in pigs (a corollary to the type of injury you might get when weight training), the swelling was greater in the limbs that were treated with ice. But in the study (as well as in another study entitled Cryotherapy Influence on Posttraumatic Limb Edema) the chilly little animal subjects were iced for very long periods of time—up to one hour in length. That is well beyond what any sports doc would recommend you do on your sprained (or is it strained?) limb.
Another study that is commonly cited in the argument against icing is the 2008 study Is Ice Right? Does Cryotherapy Improve Outcome for Acute Soft Tissue Injury? This literature review of cryotherapy research concluded: “There is insufficient evidence to suggest that cryotherapy improves clinical outcome in the management of soft tissue injuries.” So the jury is definitely still out on this one.
Does Ice Reduce Swelling?
One of the reasons your muscles get sore after a hard workout is due to the swelling which places pressure on your nerves and tissue. Controlling swelling around an injury is important because excessive swelling can create a low oxygen (hypoxic) environment that can lead to additional tissue damage, which in turn can slow healing. Swelling can also cause enlargement in joints and other tissues and irritate some nervous system components called mechanoreceptors (specialized neurons that transmit mechanical deformation information). This can also contribute to pain and soreness.
Aside from the study cited earlier that showed a potential for increased swelling after icing, it is generally acknowledged that if you have a soft tissue injury, icing should be started as soon as possible after the unfortunate event, for a duration of 15 to 20 minutes. You don’t even have to do anything fancy either, you can just use frozen ice cups, a bag of frozen peas, or crushed up ice cubes in a cloth.
For full body muscle soreness and swelling that isn’t caused by any particular injury, cold immersion works well, and can be done by simply spending 15-20 minutes in a cold bath (55 degrees Fahrenheit is adequately cold) or by taking a cold shower (as cold as your shower will go).
Cryo Chambers?
One new-ish recovery craze involves a fancy cold chamber, that looks like a single stall shower tube, that you step right into. Despite its growing popularity, the science behind these devices is pretty darn lacklustre. In 2016, the U.S. Food and Drug Administration actually stated that there is no evidence these technologies help to ease muscle aches, insomnia, anxiety, or provide any other medical benefit. In a Scientific American article, the FDA added to that statement, saying that it “has not approved or cleared any whole-body cryotherapy devices, and we do not have the necessary evidence to substantiate any medical claims being made for these devices.” The agency went on to say that it based the warning on its own informal review of published literature and generally recognized hazards associated with exposure to the gas that creates the cold conditions in the treatment chamber.
So, rather than paying big bucks (and I do mean big) to step into one of these fancy cryotherapy chambers, you can easily achieve the same or perhaps superior results with an icy cold shower or by diving into a cold pool, river, lake, or by simply turning off the heater in your car or in your home every once in a while.
More and more research is saying that cryotherapy doesn’t even deliver the same level of benefit that water exposure does. This is summed up nicely in the study called Cold Water Mediates Greater Reductions in Limb Blood Flow than Whole Body Cryotherapy, where they concluded that “Greater reductions in blood flow and tissue temperature were observed after Cold-water immersion in comparison with whole-body cryotherapy.”
This can likely be mostly chalked up to the fact that these chambers just make your skin cold, not your muscles. In fact, in a 2014 analysis of ice, cold-water and whole-body cryotherapy studies, they found that ice packs provided the biggest reductions in skin temperature and intramuscular temperature. 10 minutes of ice-pack usage cooled the skin between 32 and 47 degrees F, while three minutes of whole-body cryotherapy (the recommended time limit) resulted in between only six and 35 degrees F.
For my own experience, if these chambers could provide all the benefits that they tout (and they do tout a lot) then everyone who grew up (like I did) in a wintery cold environment would likely live forever. Or at least, never get injured.
Whether or not the Cryotherapy Chamber had an effect on my longevity has yet to be seen. Ask me again in 90 years, I guess.
I have used a cryo chamber a number of times and although it was fun and provided me with a bit of a non-caffeinated pick-me-up during some mid-afternoon sleepies, I can’t say that it cured my aches and pains, helped me burn fat, or protected me from seasonal illnesses. Whether or not it had an effect on my longevity has yet to be seen. Ask me again in 90 years, I guess.
Does Ice Actually Help or Not?
So, at this point, you are likely as confused as I am and that is not due to my poor writing or research. It is a complex topic with staunch supporters on both sides.
A fellow fitness writer named Alex Hutchinson sums up this complex issue using an Australian experiment. The experiment found that ice baths in water at 59 degrees Fahrenheit accelerated athletic recovery when compared to tepid baths of 95 degrees. But the complication comes in when the subjects in this test found the tepid baths along with a special “recovery oil” even more effective for their recovery. The trick here was that the recovery oil was just plain old bath soap, nothing more and nothing less.
Our expectations dictate our perceived recovery.
Hutchinson believes that this shows “our expectations dictate our perceived recovery.” Placebo effect anyone? To add even more confusion, it also turns out that there are “responders” and “nonresponders” to cold exposure.
In a study called Can cold water immersion enhance recovery in elite Olympic weightlifters?, the researchers once again investigated whether cold water immersion after a very hard training session could enhance recovery in elite Olympic weightlifters. However, rather than studying the entire group of weightlifters as a group, they took into account each athlete's individual response to cold water immersion.
In the end, some athletes did indeed experience significant improvements in performance and testosterone to cortisol ratios when using cold water immersion after their workouts during this three day period, while some athletes did not. The researchers concluded that there can be both “responders” and “non-responders” to icing and cold after a workout. So, I guess it is up to you to determine which one you are before you spend too much time or money on it.
When To Use Cold?
One final caveat is that cold exposure should happen long before or well after any type of workout. Sure, it feels good to dunk yourself in an icy river after a long run or to hop into a refreshing cold shower after a hard CrossFit WOD but research is against it. A study called Does Regular Post-exercise Cold Application Attenuate Trained Muscle Adaptation? found that blunting post-exercise inflammation may reduce your body’s adaptive response to workouts. Like I said at the beginning of this icy journey, your muscles becoming swollen during exercise and that is a part of how we become stronger.
Also, as we talked about earlier, cold exposure can inhibit the function of the lymphatic system in clearing inflammatory toxins from the bloodstream. So, resist the cool urge and do some foam rolling instead and wait for a couple hours (or more) after your workout before you expose yourself to the cold.
Brad Kearns, former world-ranked professional triathlete turned Guinness World Record holding speed golfer, thinks that the best time for cold exposure is likely first thing in the morning (for a cellular and central nervous system energizer), and also closer to bedtime, in order to help lower body temperature, which can help you get a good night’s sleep.
So yeah, there is evidence to suggest that when you’re doing a certain amount of resistance training, frequent use of icing or cold water immersion may blunt the training response, and possibly inhibit muscle and strength building. But, with the other benefits that cold can provide our achy and tired muscles, we need to consider more than simply whether or not cold exposure can maximize our gains or not. Especially when with a little bit of planning we can keep our cryotherapy and exercise separate and therefore have our ice and soak in it too.
As for me, I am going to stick to my hot-cold contrast showers and semi-regular exposure to Alberta winters.
I hate to sound like the guy who is always hedging his bets, but I say if it feels good and isn’t getting in the way of you reaching your fitness and performance goals, go ahead and ice your brains out. If even the idea of getting in a cold shower is akin to whacking yourself in the head with a frozen hockey puck, the evidence is not convincing enough for me to pin you down and pry that puck out of your frozen and inflamed hand.
As for me, I am going to stick to my hot-cold contrast showers and semi-regular exposure to Alberta winters.
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