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To Ice or Not to Ice: That is the question

June 1, 2018

By Phil Page, PhD, PT, ATC, CSCS, FACSM

Ice has gotten a bad rap recently. Anti-ice proponents have stated that “icing doesn’t work,” and ice has “never been proven effective.” Such statements are biased, inaccurate, and just plain wrong. Unfortunately, these claims have done nothing but create confusion and even anger. It’s easy to make these statements by looking at a few selected studies that support the anti-ice position while ignoring the hundreds of other studies on the benefits of cryotherapy.

The good thing about the anti-ice movement is that it makes us take a step back and re-evaluate the clinical decisions we make—and why we make them. Are they based on “tradition” or evidence? This article will help you understand the facts about ice to help YOU make the decision whether to use ice or not.

In a survey of Cramer First Aider readers, 97% (nearly 450 individuals) stated that they believe in applying ice to acute injuries. So, despite the negative press and false accusations, proponents of ice are still doing the right thing. Yes, icing immediately after an acute injury is correct and has lots of evidence to support it. But how do you defend your decision against the nay-sayers?

It is important to note that while the scientific literature on cryotherapy is quite vast, it remains plagued with poor quality clinical studies and few studies on injured populations; in addition, the heterogeneity among ice application in terms of time and type limits generalizability. Much of what we know about the physiological effects of ice on the healing process is based on animal studies, where extraneous variables are easier to control and obviously subjects are easier to recruit.

The most confusing anti-ice claim is that ice impedes the healing process, particularly the inflammatory phase, potentially leading to an increase in swelling. Some claim ice delays healing because it does not allow the body to go through the textbook phases of healing: injury, inflammation, repair, and remodeling. And in doing so, they claim this delay causes a buildup of metabolic waste and fluid (edema).

Interestingly, the same argument was addressed in 1975 by the ice-research guru, Dr. Ken Knight [1]. While inflammation is a natural and necessary phase of the healing process, the inflammatory mediators can sometimes do more harm than good. Remember that acute trauma, such as an ankle sprain, is relatively isolated to one or two ligaments; however, the inflammatory response may consume a much broader area, filling the entire lateral compartment. The inflammatory mediators may be necessary to heal the ligaments, but they can cause harm to uninjured tissues in the area.

Dr. Knight noted that ice essentially “dampens” the negative effects of inflammation on associated tissues by reducing the “secondary injury.” He did not identify ice as an ‘anti-inflammatory’ per say; rather, ice slows down tissue metabolism and circulation, delaying and reducing the inflammatory response to reduce the amount of residual injury. Through hypothermia and vasoconstriction, ice actually decreases the amount of waste material that must be removed from the injury site [1].

Other researchers have supported Dr. Knight’s position on reducing secondary injury with ice [2, 3]. In addition, a recent animal study [4]confirmed that while inflammation is reduced or delayed, ice does not affect the healing process. Furthermore, no studies have shown that ice actually increases swelling; in fact, a systematic review of animal studies [5]confirmed that cryotherapy significantly reduces edema after acute trauma.

While the physiologic research behind cryotherapy mechanisms provide convincing evidence, several systematic reviews of randomized controlled trials evaluating cryotherapy after injury have concluded “insufficient evidence” due to the low quality of available studies [5-9]. In addition, most studies use swelling or other surrogate measures as the main outcome variable, which may not be the best outcomes to determine “effectiveness” of ice, as opposed to a functional outcome such as ‘return to activity.’

There is no direct evidence that ice impedes healing after acute trauma or return to activity. A systematic review [10]concluded that cryotherapy may have a positive effect on return-to-sport. One found that early cryotherapy (<36 hours) after injury was associated with significantly faster return to activity compared to delayed cryotherapy or heat[11]. With ice, timing may be everything. Bleakley and colleagues [6]noted, “The sooner after injury cryotherapy is initiated, the more beneficial this reduction in metabolism will be.” Therefore, the conclusion that ice is not effective is egregiously false.

While there is no direct evidence that ice is harmful to the healing process, its use as a recovery tool is questionable, particularly after intensive eccentric exercise (such as pitching). This may be because the recovery process is different from the healing process. It is unwise to equate recovery to healing from a physiological perspective until scientists can identify specific mechanisms associated with recovery such as delayed onset muscle soreness (DOMS).

Aside from acute trauma (<48 hours after injury), ice probably does not help beyond pain reduction. Ice alone doesn’t directly reduce swelling, which has been confirmed in several studies [12, 13]. However, ice’s ability to reduce pain makes it an effective and safe alternative in pain management. It’s been well established that pain and swelling can inhibit muscle strength; therefore, it would be wise for practitioners to address pain with safer cryotherapy alternatives to initiate movement as soon as possible. That’s where therapeutic exercise and muscle activation comes in. “Cryokinetics,” or the use of cold to facilitate exercise, can play a key role in a rehabilitation program [14].

Yes, sometimes ice is over-used and sometimes claimed to do things it probably doesn’t do. While there are some circumstances where ice may not be appropriate or helpful, blanket statements like, “Ice is wrong” is both inaccurate and unfair. The science supports ice in some situations, but the research is often insufficient to make a definitive conclusion on when to use ice or not. Until ice is directly proven harmful to healing (which is unlikely), it remains a gold standard of treatment in acute injuries.


1. Knight, K.L., The Effects of Hypothermia on Inflammation and Swelling. Athletic Training.Athletic Training, 1975. 11(1): p. 7-10.

2. Ho, S.S., et al., The effects of ice on blood flow and bone metabolism in knees.Am J Sports Med, 1994. 22(4): p. 537-40.

3. Merrick, M.A., et al., A preliminary examination of cryotherapy and secondary injury in skeletal muscle.Med Sci Sports Exerc, 1999. 31(11): p. 1516-21.

4. Vieira Ramos, G., et al., Cryotherapy Reduces Inflammatory Response Without Altering Muscle Regeneration Process and Extracellular Matrix Remodeling of Rat Muscle.Sci Rep, 2016. 6: p. 18525.

5. Collins, N.C., Is ice right? Does cryotherapy improve outcome for acute soft tissue injury?Emerg Med J, 2008. 25(2): p. 65-8.

6. Bleakley, C., S. McDonough, and D. MacAuley, The use of ice in the treatment of acute soft-tissue injury: a systematic review of randomized controlled trials.Am J Sports Med, 2004. 32(1): p. 251-61.

7. Yerhot, P.S., T.; Wienkers, B.; Durall, C., The efficacy of cryotherapy for imrpoving functional outcomes following lateral ankle sprains.Ann Sports Med Res, 2015. 2(2): p. 1015.

8. van den Bekerom, M.P., et al., What is the evidence for rest, ice, compression, and elevation therapy in the treatment of ankle sprains in adults?J Athl Train, 2012. 47(4): p. 435-43.

9. Malanga, G.A., N. Yan, and J. Stark, Mechanisms and efficacy of heat and cold therapies for musculoskeletal injury.Postgrad Med, 2015. 127(1): p. 57-65.

10. Hubbard, T.J., S.L. Aronson, and C.R. Denegar, Does Cryotherapy Hasten Return to Participation? A Systematic Review.J Athl Train, 2004. 39(1): p. 88-94.

11. Hocutt, J.E., Jr., et al., Cryotherapy in ankle sprains.Am J Sports Med, 1982. 10(5): p. 316-9.

12. Song, M., et al., Compressive cryotherapy versus cryotherapy alone in patients undergoing knee surgery: a meta-analysis.Springerplus, 2016. 5(1): p. 1074.

13. Cote, D.J., et al., Comparison of three treatment procedures for minimizing ankle sprain swelling.Phys Ther, 1988.68(7): p. 1072-6.

14. Knight, K.L., Cryotherapy in Sport Injury Management. 1995, Champaign, IL: Human Kinetics.