Ice is one of the most commonly used treatment interventions following injuries. Nearly anyone who plays sport has heard the term RICE, and knows that the “I”, or icing, is often the immediate and most pressing thought – not only when managing an acute injury, but often extending well into the rehabilitation program!

So, why is ice application so important? Ask 100 people in a sporting environment, and the answer from 99 of them will probably give is “to reduce swelling”. Well, it may surprise you all to realise that there’s not really any evidence to support the reduction of swelling theory!

To reduce swelling, ice application would have to reduce metabolism and for this to happen, the tissue temperature at the injury site would have to reach between 5 and 10 degrees – at depth, not on the surface. No study has been able to demonstrate this at a depth of even 2cm below the skin tissue, and there is no evidence for the ability of ice to reduce metabolism in the human tissue.

What About Inflammation?

So if ice doesn’t reduce swelling, does it reduce inflammation (are the two actually even different)?

Inflammation is a crucial process in the body that has the following critical functions:

  1. To defend the body against alien substances
  2. To dispose of dead and dying tissue
  3. To promote regeneration of tissue

There are five major signs of inflammation, only one of which is swelling. Swelling is not inflammation, it is an indicator that an inflammatory process is in place. Swelling is the result of bleeding from the acute injury or trauma. If Inflammation is essential for healing to occur, as outline above, we really don’t want to be diminishing the inflammatory response which would just delay healing; however limiting the swelling may be advantageous. Prolonged swelling (often called oedema) has many harmful effects: swelling may result in slower blood flow around the injury and less oxygen being delivered to both the damaged cells and the nearby healthy cells, causing secondary damage. With ongoing secondary damage, the inflammatory process may become prolonged, and this is where problems arise.

The summary of this is that inflammation is not only good, it is a necessary component of healing. Swelling is an unfortunate by-product of injury and inflammation, but persistent swelling may cause inflammation to persist beyond the helpful phase. This helps to explain why, in many cases, anti-inflammatory medication is not commonly used in acute injury (because we need the early inflammation) but may be used as symptoms persist beyond optimal time periods. If we don’t want to inhibit early inflammation, then it makes sense that the purpose of ice is not an anti – inflammatory one.

So Why Ice?

The major reason for the immediate application of ice seems to be for the purpose of producing an analgesic, or pain relieving, effect. To produce a local tissue analgesia, studies suggest a temperature between 10 and 15°C is optimal, and this is readily achievable with most ice modalities. There are many scientific papers that support the benefits of using ice for pain relief.

Ice would seem to have major benefits in the following situations:

    1. Acute injury, expected return to play: after no structural damage has been determined, icing to reduce pain to allow a prompt return to the field is appropriate. Crushed ice in a plastic or material bag is best as it has been shown to reduce skin temperatures to the critical level required for analgesia within 5 minutes (Jutte, Merrick, Ingersoll & Edwards, 2001; Merrick, Jutte & Smith, 2003).
  • Acute injury, structural damage, no return to play: for more severe injuries where return to play is neither expected or advised, then ice can still be applied for pain relief. However the critical modality in this case is compression! Compression reduces the available space for swelling (the undesirable side effect) to collect, whilst not inhibiting inflammation (the desired side effect). Compression also reduces swelling by promoting reabsorption of the extra fluid that does gather. In this case, ice should be applied in a plastic bag and attached with a compression bandage. Note that the ice is not the most important criteria here, it is the compression.
  • During Rehabilitation and Recovery: Understanding the above means that icing during rehabilitation will only really be effective if pain is the issue. If managing or preventing swelling is the issue, then compression should be the strategy used. However, we know that the earlier exercises (the correct ones) are started post injury, the better the recovery. One strategy for ice in the early rehabilitation period is to ice the area, create an analgesic effect, and then get the person to perform 25-10 minutes of safe exercise, then ice again, and repeat the exercises. The idea being to enable the person to complete some important exercises that would otherwise have been too painful! These exercises are not only important for strengthening and range of movement, but for stimulating healing in the tissue, and also creating movement to help pump swelling away.


One Further Point About Ice

Perhaps another poorly understood concept about ice: “How long do I ice for”? Answers range from once only after injury, to 20 minutes every two hours, to 20 minutes on/20 minutes off!

It appears the best rationale for ice is 10 minutes on, 10 minutes off, and this is explained as follows:

  1. Dependent on the ice modality used, temperatures can begin to rise in the modality after 10 minutes (eg conduction of heat from the body surface causes your ice modality to begin to warm up, reducing its effectiveness).
  2. 10 minutes ice creates a cooling gradient at depth between the skin and the damaged internal tissue, When the ice is reapplied for a second 10 minutes, the tissue temperature at depth has not risen to pre-treatment levels and therefore can reach a lower temperature still. So, rather than the traditionally 20 minutes continuous, where the modality may start to warm after 15 minutes, here you still receive a combined total of 20 minutes ice application, but the tissue is maintained at a lower temperature for over 30 minutes.


Do Cold Sprays & Instant Cold Packs Work?

In the words of Peter Thain, upon whose work which much of this blog is based: “I must say, cold sprays have come in very useful… I use it as pest control to kill the flies and gnats in my therapy room”! No more to be said!

The standard gel packs in most sports kits also have minimal purpose. Think of it like this – if you gathered 30 of your team in a circle and passed a crushed ice pack from person to person, the 30th in line will still receive an extremely cold package. However the gel pack would almost be at room temperature by the 30th handling: they just do not absorb heat as well as crushed ice, therefore heat up quicker and have far less skin cooling potential. No doubt, ice based modalities are superior to gel packs at reducing skin temperature.

What does this all mean?

In a nutshell, the inflammatory response is an essential part of healing, and no attempt to stop it should be made. The main goal in the acute treatment of an injury and during rehabilitation is to limit and then aid the removal of swelling, and compression (and elevation) achieve this with greater success than ice application. Ice would appear to have its greatest benefit in pain relief and enabling early rehabilitation to occur.

What About Beach Therapy?

Why are all those AFL footballers standing in the ocean, risking pneumonia in the middle of winter? Is it the cold for analgesia, or is it perhaps the amazing compressive properties that water has (you know what it’s like on your ears even when you dive to a shallow depth). I’ll leave that argument for another blog!

Anthony Lance

SSPC Physiotherapist



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