Recently I have been asked by several clients “what should I put on my injury, ice or heat? And what are the differences?” As physiotherapists, we see a lot of injuries ranging from new to old. For the most part, people are familiar with the acronym R.I.C.E – rest, ice, compression and elevation. But is this up-to-date practice? Let’s review this topic to try and give a confident, well-informed answer to this common question.
Ice. It is one of the most common treatments used around the world. Ice works by constricting the blood vessels and reducing tissue metabolism. Basically, it slows down any bleeding, swelling and how the tissues work as a whole. There is also evidence that once the skin temperature falls below 15®C then there is an analgesic (or pain relieving) effect. This is because the nerves conduct their messages more slowly at lower temperatures. Research shows that a standard application of ice after a soft tissue injury consists of a crushed ice bag with a towel between the skin and ice to avoid frostbite/ice burn. This should be held over the affected area for 20 minutes and reapplied every two hours for the first six hours. Furthermore, there is evidence that shows a combination of ice and exercise is more effective than exercise alone at healing injuries.
In comparison, heat works by opening up the blood vessels, thereby increasing the blood flow and making the tissues more elastic. Heat can also produce its own pain relieving effect. In the acute stage after an injury (within the first five days), there is evidence to suggest that applying heat can actually make the injury worse due the increased bleeding and swelling. Therefore, the use of heat is more effective on injuries that are more longstanding. For example, heat can decrease joint stiffness and pain in people with osteoarthritis and can be used as a relaxant on sore muscles and trigger points. Interestingly, there are studies that have shown heat therapy provides short-term reductions in pain and disability in people with acute low back pain and provides significantly greater pain relief of Delayed Onset Muscle Soreness (DOMS) than cold therapy.
Overall, after reading the research on this cool topic, the results are inconsistent. For me personally, if a person came to me with an acute rolled ankle, I would recommend that they ice the injury for 20 minutes every three to four hours, for the first week. However, if a person came in with a four month history of neck pain and stiffness, with associated soreness in the surrounding muscles, I would suggest they apply heat for 30 minutes a day over the area. Above all else, I believe in personal preference and past experiences to guide the decision. Others may differ from this but you and your physiotherapist can discuss this further to come up with a tailored plan for your needs.