The use of ice and heat for at home treatment of an injury and pain relief is common. However it is often confusing to know which one to use, when to use it, how long and how often to apply it. In fact, one of the most common questions we get from patients is, “should I use ice, or heat?”. The best way to answer this question is to first understand how ice and heat work to alleviate pain, and then know when to use them appropriately.
Ice works as a vasoconstrictor, which means that while it is applied to the skin it will temporarily constrict the blood vessels. This constriction helps to slow the flow of fluid that promotes inflammation. Ice also helps to decrease the perception of pain by slowing the pain signals from nerves in the area applied.
Heat is a vasodilator that will temporarily dilate the blood vessels increasing the flow of blood to the area. This allows for the relaxation of muscles and alleviates stiff joints making the area more loose and flexible. The increase in blood flow to the area also brings in new nutrients to help heal injured tissues.
Ice is best used in acute or traumatic injuries, any injury occurred during physical activity, overuse injuries, and muscle spasms. An easier way describe these injuries would be to think about pulled or strained muscles, sprains to joints like ankle or wrist, or impact injuries such as bruises or jammed fingers. Overuse or recurrent injuries are conditions such as tendonitis, shin splints, plantar fasciitis, etc. that tend flare-up if not appropriately treated benefit from ice therapy. Ice should be used within the first 72 hours following an injury. Ice should be applied for 20 minutes at a time and can be used hourly or in 2-3 hour intervals depending on the severity of the injury. Heat therapy can be used 72 hours after an initial injury.
Heat is best used in chronic conditions, or in situations where relaxation and flexibility of the tissues is needed. Heat should be used before activity to help loosen muscles and alleviate stiff joints. Heat should NOT be applied in a “fresh” or “new” injury, but can be applied 72 hours after an initial injury or when there is no obvious sign of swelling or inflammation. Heat is best used for trigger points or “knots” in the muscle, stiff joints from arthritis, or after exercise. Heat should be applied for 20 minutes at a time as well. Longer amounts of time can be used for different forms of heat therapy (like a warm bath, hot tub or sauna) or if it is not being used to treat an injury.
In short, if the injury is “acute”, “fresh”, or “new”, use ice first. If you feel stiff and tight, and have for a while use heat first. Use both forms of therapy for only 20 minutes at a time. Both forms of therapy provide an easy and inexpensive way to treat pain at home and provide relief temporarily. Lastly, if you have an injury, be sure to have it assessed by your healthcare provider.