What Research Says on the When and How to Use Ice

Brooke Thomson

May 19, 2021

Ice therapy is one of the staples of the home first aid system; a bag of frozen peas is often on the front line of defense for minor injuries. We use ice for such a diversity of ailments it’s difficult to even start narrowing down when it is or isn’t useful. The New York Times recently reported a new study from Japan shows that ice may be detrimental to athletic recovery. A deeper look shows that this is actually consistent with many studies performed through the 2000’s, and this isn’t exactly “new” news for researchers. But in light of this research, why has ice been used as a silver bullet in recovery for decades?

Athletes have long used an icy bath after work outs, many spas incorporate a cold plunge or shower, and cryotherapy chambers are gaining popularity as a recovery method. The cult-like but increasingly popular following of Wim Hof adheres to regular ice baths combined with breathwork techniques. Considering a growing popularity in cold therapy treatments when is ice an effective treatment? Here we will uncover the perceived and real benefits of ice treatment in the very wide scope that ice is commonly used to remedy. For a similar exploration of ice's counterpart, heat, look here.

Ice For Acute Injury: (sprains, broken toe, swelling, etc)

Con: Many studies through the 2000’s show that ice will slow down cell regeneration needed for a recovery
Pro: Ice will reduce swelling/inflammation.
Pro: Ice will numb pain making it more bearable.
Con: An injury swells in order to increase blood circulation to the area. This brings the injury cite needed blood cells and carries out dead tissue cells. By slowing the blood and tissue cell circulation, ice impedes the healing process.
Con: Dr. Gabe Merkin who coined the acronym R.I.C.E. (Rest, Ice, Compress, Elevate) in 1978 later published “Why Ice Delays Recovery” in 2015 to explain how further evidence actually disproves his widely accepted R.I.C.E. principal.
Con: Ice may actually increase cell death post-injury. A lack or loss of blood flow will not only slow a cell’s regeneration but can also kill more existing cells in the area. Circulation has proven to be critical for wound healing.
Conclusion: Ice will reduce the inflammation around an acute injury and numb pain. It can be used immediately as a quick-fix but it’s creating the impression of healing rather than assisting the body to heal.

What about skeletal muscle pain such as sore muscles after a work-out or to reduce whole-body inflammation that is the root cause of so many other conditions ranging from auto-immune disorders, depression, to eczema? Can whole body cryotherapy or cold plunges have merits?

Ice for Muscle Recovery: (post-work out or chronic back pain)

Con: The new study from Japan is one of many that show ice slows down regenerative tissue growth after intense muscular exertion. The study used E-Stem on mice for intense muscle contraction, but many previous studies with athletes in the past 20 years show similar results
Pro/Con: Ice therapy will delay lactic acid (that causes soreness) but not prevent it. Several studies reflect that consistently icing after training diminishes muscle growth. It will help with perceived discomfort, but it will slow down and diminish the overall results.
Con: While examining muscle development it was found that athletes who iced had smaller blood vessels than the control group who did not ice. This would have negative implications for muscle tissue regenerating (consistent with many other studies) along and an indicator that ice diminishes the cardiovascular system
Pro: For chronic muscular pain, ice will numb and provide short term relief. But just not useful in long term healing.
Conclusion: An ice bath will stave off soreness for an athlete who needs to get back on the field in a short amount of time. But repeated icing after exertion will slow muscle growth.

Chronic Inflammatory Conditions: (rheumatoid arthritis, eczema, tendonitis)

Pro/Con: The same way ice reduces swelling in an acute joint injury, full body icing may be useful. One study has shown significant pain reduction in the 90 minutes after cryotherapy, but no evidence of long-term improvement.
Con: While we’re at it, ice may not be best to treat chronic tendonitis issues such as Tennis Elbow. Often inflammation is thought of as the source of tendonitis/bursitis but it's more accurately cell degeneration causing inflammation in this case. Just like with acute injuries, ice will impede the circulation of blood to the affected area and restrict cell generation.

Anxiety/Depression:

Pro: The shock of an ice bath or cold shower does release hormones that positively affect mood. The theory with this is that creating a physical stressor for just a couple minutes releases flight or fight hormones that later provide a “feel good” sensation similar to how exercise improves mood.

Metabolism and Weight Loss:

Ice diminishes muscle regeneration. For ideal weight loss the goal is to convert body fat to muscle so ice baths or cryotherapy is probably not helpful for weight loss
Brown Fat: Wim Hof and Cryotherapy spas advertise that ice baths reduce brown fat. While this is true, there isn’t a known role of brown fat in weight loss. Conversely it is better researched that the body holds onto fat cells when under stress. The body will use brown fat cells to regulate temperature, but it may will bolster other fat cells to insulate the body
The most promising study used subjects that were exercising daily during the study, so unclear if their weight loss was connected to exercise or if the cold therapy correlated to weight loss

Contrast Therapy:

Contrast Therapy where one uses hot and cold temperatures seems to have the most positive effects.

The reason why contrast therapy can be more effective than just ice therapy is that it’s creating a more powerful blood flow through the body. An ice plunge constricts blood flow. When the body heats up again, vessels will dilate and the heat will act as opening floodgates. So in alternating hot/cold patterns ice therapy can be used to increase blood flow useful. It’s also more comfortable and the body may perceive it as less of a stressor.

So jumping into an ice bath immediately after a work out while the body is still hot, and then followed by a hot shower would effectively work as contrast therapy. So would a cold plunge in a spa. This is in line with Scandinavian traditions of alternating a sauna with a dip in icy water.

In Conclusion:

Ice works for delaying swelling, bleeding, and muscle soreness. It will also numb the area for pain relief. It has not been shown to help long term healing and actually works against the body’s healing mechanisms. One more thing, don't use ice for burns either. The most positive research may be using ice baths to improve mental health. A real question from all of this is why have we relied on ice to the extent that we see it as a silver bullet treatment?

The answer may be that we have a fixation with the fastest solution rather than the best solution. Another answer may be that we treat our bodies with a “no pain no gain” attitude that even applies to recovery. There’s a feeling that by subjecting oneself to a more extreme recovery method will make a faster recovery. Lastly, all too common our perspective is to fix symptoms rather than causes. Ice will quickly reduce swelling and numb pain leading to the impression it is healing.

At the end of the day, perceived benefits are just as powerful as real ones. Taking an action like a cold plunge may make one feel more empowered or be enjoyable. So if it makes you feel better and if you feel inclined to join Wim Hoff for ice bath, follow your bliss.