A common question that I get from patients is, “Should I use ice or heat?” My immediate response is always, “It depends.” The debate of whether to use ice or heat depends on numerous factors, including the type of injury/ailment and the chronicity of the injury (i.e. time since injury onset). I will take this time to discuss the indications and contraindications for ice and heat, based on both the current research and my clinical expertise.
One of the purposes of cryotherapy/cold therapy is to decrease blood flow and the subsequent flow of inflammatory cells to an injured area in order to prevent or decrease swelling and inflammation. The application of ice also temporarily inhibits nerve conduction, decreasing the pain signals that travel from the injured site to the brain, thereby decreasing our perceived level of pain. Cold therapy has also been shown to alleviate muscle spasms by inhibiting the spinal cord reflex loop.
When to use
Since one of the reasons for cold therapy is to decrease swelling, I tend to suggest using ice during the first 48-72 hours following a traumatic injury (e.g. an ankle or knee sprain or a muscle strain) and for the first few weeks following an orthopedic surgery (e.g. total joint replacement). However, since the acute inflammatory process is a normal and necessary part of the body’s natural healing process, some inflammation is, in fact, a good thing. For this reason, some healthcare providers may argue against the use of ice following an acute injury or surgery, as they believe that it will delay or impair the recovery process by altering the body’s natural healing process. Yet, a recent study performed on rats with an induced muscle strain suggests that cryotherapy decreases the amount of cellular inflammatory markers without altering the regeneration of muscle and the surrounding tissue.5 In this study, the ice was applied for 30 minutes, every 2 hours, for the first 48 hours following the injury. 5 Based on this study, cold therapy appears to decrease the amount of inflammation, at least on a cellular level, without delaying recovery.