Hot and Cold Therapy

Hot and cold therapies are the oldest form of treatment used to treat swelling, inflammation, muscle spasm and pain.

Hot therapy aims to induce vasodilation which draws blood into the target tissues.  The increase in blood flow delivers much needed oxygen and nutrients, and removes cell wastes.  Additionally, the warmth decreases muscle spasm, relaxes tense muscles, relieves pain, and can increase range of motion.  Hot therapy can come in many forms including, hot packs, hydrotherapy and topic gel agents,

Cold therapy, or cryotherapy, produces the opposite effect to heat, vasoconstriction, which slows circulation reducing inflammation, muscle spasm, and pain.  Cold therapy is available in many forms including ice cubes, iced towels or compresses and cold packs.

When using either hot or cold therapy caution is paramount.  You must ensure that the skin over which the therapy will be applied has normal sensation.  You must never apply cold or ice or hot packs directly to the skin.  A barrier, such as a towel, should be placed between the skin's surface and chosen therapy to prevent skin and nerve damage.

When to use hot or cold therapy?

The choice of when to use hot or cold therapy depends on the condition and symptoms.  We typically classify injuries into 2 categories.

  • Acute is of rapid onset and short lived.  They are sudden, sharp and traumatic.  Symptoms include the first signs of inflammation: pain, redness, heat  and swelling
  • Chronic develops slowly and is persistent and long lasting.  Symptoms include a dull pain or soreness that often comes or goes.  If an acute injury does not heal and the symptoms persist, the condition is then classified as chronic

Cold therapy with ice is the best immediate treatment for acute injuries because it reduces swelling and pain.  Apply ice (wrapped in a thin towel for comfort) to the affected area for 10 to 15 minutes at a time.  Allow the skin temperature to return to normal before icing a second or third time.  You can ice an acute injury several times a day for up to three days (see our PRICE guidelines for further information on treeating acute injuries).

Cold therapy is also helpful in treating some overuse injuries or chronic pain in athletes, e.g. chronic knee pain that increases after running may want ice over the injured area after each run to reduce or prevent inflammation.  It's not helpful to ice a chronic injury before exercise

Heat is generally used for chronic injuries or injuries that have no inflammation or swelling.  Sore, stiff, nagging muscle or joint pain is ideal for the use of heat therapy.  Heat can also help relax tight muscles or muscle spasms.  Don't apply heat after exercise.  After a workout, ice is the better choice on a chronic injury.  Heat increases circulation and raises skin temperature, and should not be applied to acute injuries or injuries that show signs of inflammation.