When To Use Heat On An Injury

Heat has been used for thousands of years in the treatment of different types of pain. Experience shows that it has a beneficial effect on pain arising from inflammation, which is the body’s defense mechanism in cases of injury due either to accident or to overuse. Injuries caused by trauma or overuse, such as ligament injuries and muscle ruptures, are often treated during the acute stage by cooling and bandaging so that the bleeding in the injured area is limited. After the initial 48 hours, heat treatment can be introduced to help the healing process. Heat may be started once the risk of hemorrhage is over, and aids healing by increasing the blood flow to the injured area.

If an injury is treated by heat applications in its acute stage the blood vessels expand, and the blood clotting procedure may be disrupted. The amount of fluid in the tissue increases. This leads to increased bleeding in the injured area, increased swelling and higher pressure in the surrounding tissues. The result may be more pain and slower healing than would otherwise be the case.

Perhaps the most important effect of heat treatment is its influence on collagen fibers. A tendon is composed of 90% collagen fibers and 10% elastic fibers. Collagen has viscous and elastic properties, which means that the more rapidly a tendon is loaded, the stiffer it becomes. Heat increases elasticity and plasticity, so after its application the collagen fibers become more flexible and more capable of rehabilitation exercises. Heat also decreases joint stiffness and relieves muscle spasm. This reduces the risk of injury.

Heat can be used in both the prevention and rehabilitation of overuse injuries and to combat the aftereffects of torn muscles and tendons. It can be valuable during warm-up before training sessions and competitions and in cold weather, increasing the mobility of joints.