Ice vs. Heat

One of the most often asked questions in our clinic is “Should I use ice or heat for my problem?” Most of us have heard of RICE (rest, ice, compression, elevation) for sports injuries but do not realize that ice is the best treatment for all acute injuries, including stiff necks, sore backs, and muscle pulls.

With any injury to a muscle, tendon, ligament, or joint, the body reacts with only one mechanism, inflammation. Although inflammation is needed for the repair process, the body’s reaction is usually in excess of what is required. Therefore, ice is needed to decrease the swelling of the injured tissue, which it does by constricting the surrounding blood vessels. Ice also slows down the cell metabolism of the injured area and prevents any secondary damage by decreasing its need for oxygen. Ice can reduce pain by slowing the nerve conduction of the pain receptors and thus reduce the reactionary muscle spasm.

There isn’t any strict time frame for ice application, but ice is usually put on for 10 to 20 minutes each hour after an acute injury. Times may vary depending on the depth of the injured tissue. A therapeutic temperature of 10-15° C is desired. If ice application is done for longer than needed, the body’s self protective mechanism will dilate the blood vessels to prevent any tissue damage.

The inflammatory stage of an acute injury usually lasts for two days. However, every injury is unique and as long as there is pain and swelling (or heat), ice should be used. Studies have shown that if ice is not used initially after an injury, the recovery period is usually longer due to the excessive scar tissue formation – one of the results of inflammation.

When pain has decreased and swelling has subsided, heat may be used to increase the transport of blood and nutrients to the injured area and aid in the removal of waste products.

Both ice and heat are considered counter-irritants. When you feel the cold or heat, you do not feel the pain. However, when heat is applied to an acute injury, more inflammation and subsequent scar tissue is produced. The resultant scar tissue is not as strong or elastic as the original injured tissue. Scar tissue also contains more pain receptors than original tissue which results in an increased perception of pain.

Ice used before exercise can reduce pain and spasm along with reducing the neural inhibition found in muscles surrounding an injured joint. This allows for greater activation of muscles during the rehabilitation process. Ice before exercise does not increase the risk of injury nor does it alter the joint position sense or sensory perception.

Ice or heat may be used on the injured area before any physical activity but only ice should be applied after any activity. When using ice or heat, use a towel to prevent any damage to the skin. If you are not sure which one to use, you can never go wrong with ice.

Cold therapy should be avoided by people who have Raynaud’s phenomenon, peripheral vascular disease, cold hypersensitivities, and diabetes with vascular involvement.

Source: Bleakley, C., MacAuley, D., What is the role of ice in soft-tissue injury management? Evidence Based Sports Medicine (2nd ed); 189-207.