Injury Treatment - Hot Or Cold?

As massage therapists a question we are commonly asked is whether you should apply heat or cold to an injury or sore/tight area. The general consensus is that you should use cold on acute injuries and heat may be more appropriate for chronic injuries.

Acute injuries are sudden injuries and usually the result of an impact, a fall or a sprain. The cause of an acute injury is normally fairly clearly (or at least the time the injury occurs is apparent). The common signs of an acute injury generally include pain, swelling, tenderness at injury site and heat/redness.

A chronic injury tends to be slower to develop with no one single event triggering the injury. The injury is longstanding although may come and go. Typically it is the result of long term overuse but can also be the end result of an inadequately treated acute injury.

Hot or Cold?

Quite simply, acute injuries need to be treated with ice as it reduces inflammation at the injury site. When combined with compression, cold therapy initially constricts the blood vessels and reduces the amount of blood that can reach the injured area. This also has the outcome of limiting any bleeding at the site of the injury. Another benefit of cold therapy is that cold can decrease muscle spasm, reducing sensitivity to stretching.

The reduced swelling from using cold therapy allows greater movement in the injured muscle/joint and so reduces the functional loss related to the injury. The swelling associated with the inflammatory response may also produce an increased pressure in the tissue, leading to the area becoming more painful. This pain is believe to be intensified by chemicals that are released into the blood when tissue is damaged and so vasoconstriction from applying ice also decreases pain.

Normal procedure is to apply ice, wrapped in a towel or something similar (ice should not be left directly applied to the skin) for around 10-15 minutes at a time. The temperature at the injury site is then permitted to return to normal and then the ice is reapplied. This ice-on ice-off procedure can be repeated, for up to a couple of days for particularly nasty acute injuries. A form of ice that adapts to the shape of the injured area works best (hence the common suggestion of a packet of frozen peas wrapped in a tea towel). Leaving the ice on for too long can result in ice burns/frostbite and the Hunting Response may result.

Application of ice is also useful in dealing with chronic injuries in athletes who are in training. For example, an athlete with a condition such as mild Achilles tendonitis who chooses to continue exercise may wish to ice the area after training (same 10-15 minutes on /off protocol applies).

Conversely heat is generally indicated in the treatment of chronic injuries. The application of superficial heat to an injured area can increase the flexibility of muscles, tendons and ligaments and also reduce any muscle spasms. The exact mechanism by which heat can reduce pain is not entirely clear although hypotheses are that heat inactivates nerve fibres or that heat may induce the release of endorphins.

Heat seems to work best for untightening muscles and improving flexibility. Blood flow increases in the heated areas of the body because the heat can relax the walls of the blood vessels. It is for this reason that it is generally not recommended to apply heat to an area that is already inflamed.

Moist heat is normally best and can be as simple as taking a bath or shower. Wet towels can also be used (but please ensure that the temperature is not too high as to cause burns). Never fall asleep when using any form of heat therapy.

As with any injury management, if excessive pain and discomfort persists after around 48 hours, then please consult your health professional.