Athletes get injured in sports all the time, and when they do, their bodies release a number of chemicals that increase blood flow to the injury site and cause inflammation. The minutes after the injury occurs are the best time to use cryotherapy to help with healing.
Although highly beneficial for healing, some chemicals also increase the sensitivity of the pain fibers in the area, making the pain more acute. Some see this as a good thing, and in the proper context it is. But too many chemicals entering the injured area can cause excessive hemorrhaging and damage to blood vessels. When this happens, new cells and uninjured cells can become hypoxic (oxygen-deprived) and die.1, 5, 6 Clearly this means healing will take longer, swelling will be slower to go down, and motor control of the muscles surrounding the injured area will take longer to return. That’s where cryotherapy comes in.
Cryotherapy is a method of applying cold to cause enough vasoconstriction (narrowing of blood vessels) to allow new cells to grow and injured cells to heal, while also getting rid of all the dead cells that don’t need to be there anymore.
But doing cryotherapy safely and effectively can be complicated, with many different cold and compression applications and timing to consider. Let’s take a look at the research to help make the decision a bit easier.
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The most common way to ice is with a plastic bag filled with ice cubes. Some physical therapy facilities or colleges may have crushed or flake ice, which conforms to body parts better but melts quicker. There are also gel ice packs from various manufacturers, as well as more expensive products like the GameReady, which funnels cold water through a plastic boot or shoulder harness to apply cold all the way around a body part. For those not faint of heart, an immersion bath, more commonly known as the dreaded “ice bucket.”
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In addition to applying cold to acute injuries, research has long shown that compression can help decrease the temperature within the muscle.3 Often you’ll see athletes with an ice bag wrapped in plastic wrap, but other options include an elastic bandage or in some controlled settings a wet elastic bandage that has been chilled in the refrigerator.
A common myth is that if you place ice directly on someone’s skin, you’ll put them at risk for frostbite. That is hilariously false. In order to get frostbite (causing so much vasoconstriction that the skin cells die from not getting enough oxygen), the skin needs to be below 32 degrees Fahrenheit for an extended period of time.
Try this simple experiment: put an ice bag directly on your skin. After 10 minutes, check the ice bag. Is the ice melting? If the answer is yes, the surrounding temperature is clearly above 32 degrees and you are in no danger.
There are two exceptions to this rule. The first is with gel ice packs that filled with anti-freeze that actually stay at a temperature of about 15 degrees Fahrenheit. With these, you should use a barrier to the skin. The other exception is for people who have a condition called Raynaud’s Syndrome, which causes an allergic type reaction when ice or significant cold is placed directly on the skin.
Remember your coach telling you to ice for 20 minutes on and 20 minutes off? Did you ever think about why your coach said that? In 1952, Dwayne “Spike” Dixon was the first athletic trainer credited with using cold therapy, at Indiana State University. At the time, no one had studied why, when, or how long to ice. When Dixon used ice for basketball athletes after the first of two practice sessions, they asked him how long they should ice. He thought about it, and asked the athletes how much time they had to eat in the cafeteria before having to come back to the gymnasium. Their response: about 20 minutes. That’s the “scientific” reasoning behind the current conventional wisdom.
A few studies actually show temperature decreases in muscle tissue based on different application methods, so we can figure out the best route to take. The answer to “how long to ice” must be individualized, not generalized. Someone with a high percentage of body fat needs longer therapy than a very lean athlete, because it takes longer for the cold to reach deep enough to affect muscle tissue. The same goes for different body parts: icing your elbow won’t require as much time as your glute muscles.
If you’re like most athletes, you probably only have access to the common cubed ice bag wrapped with plastic wrap. If that’s the case, the minimum effective dosage time is roughly 15-17 minutes. If the tissue you’re trying to affect is deeper, you can leave the ice on as long as 30 minutes. After that, typically the ice will be mostly melted and not as effective. Remember: the muscle tissue temperature still decreases for up to 90 minutes after you remove the ice.4
In an ideal setting, the quickest way to make a difference is with a gel pack wrapped with a cold, wet elastic bandage (for compression and as a barrier to the skin). If no gel pack is around, use a bag of ice. A barrier to the skin is unnecessary. For compression, go with the wet elastic bandage. If that option is unavailable, a regular elastic bandage will do just fine. As always, consult with a certified athletic trainer or physical therapist before applying cold to an injury.
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1) Merrick M. “Secondary injury after musculoskeletal trauma: a review and update.” J Athl Train. 2002 Apr-Jun.
2) Meeusen R, Lievens P. “The use of cryo in sports injuries.” Sports Med. 1986 Nov-Dec;3(6):398-414.
3) Tomchuk D, Rubley MD, Holcomb WR, Guadagnoli M, Tarno JM. “The magnitude of tissue cooling during cryo with varied types of compression.” J Athl Train. 2010 May-Jun;45(3):230-7. doi: 10.4085/1062-6050-45.3.230.
4) Rupp KA, Herman DC, Hertel J, Saliba SA. “Intramuscular temperature changes during and after 2 different cryo interventions in healthy individuals.” J Orthop Sports Phys Ther. 2012 Aug;42(8):731-7. doi: 10.2519/jospt.2012.4200.
5) Lee H, Natsui H, Akimoto T, Yanagi K, Ohshima N, Kono I. “Effects of cryo after contusion using real-time intravital microscopy.” Med Sci Sports Exerc 2005;37(7):1093–8.
6) Smith TL, Curl WW, Paterson Smith B, Holden MB, Wise T, Marr A, et al. “New skeletal muscle model for the longitudinal study of alterations in microcirculation following contusion and cryo.” Microsurgery 1993;14:487–93.