Jose G. Veliz, M.D. M.S.A.
Medical Director
Palomar Pain Management Center
Pomerado Pain Management Center

Posted December 27, 2008

When should ice or heat be used when experiencing pain?  When should ice or heat be used after injury?  This article reviews when ice or heat should be used with acute and chronic pain and/or injuries.

Injuries generally result in pain.  There are two types: 

Acute pain occurs rapidly and has a short duration period.
Chronic pain occurs slowly and lasts for long periods. 

Acute injuries occur immediately or within hours and result in pain.  The cause of acute injuries is usually clear and commonly results in redness, tenderness, swelling, inflammation, warmth and pain.  Swelling usually occurs with acute injuries but may, less commonly, occur with chronic medical conditions. 

Chronic injuries develop slowly and the cause of a chronic injury may not be as clear.  Symptoms include a dull pain or ache which may wax and wane.  The causes of chronic injuries include: 

1. Acute injuries which have not resolved
2. Improper treatment of an acute injury.
3. Repetitive use or overuse.

Ice Treatment:

In general, a recent or acute injury within the last 48 hours responds better to ice treatment.  Swelling is usually present after an acute or recent injury and ice treatments can decrease swelling.  Swelling represents an inflammatory reaction with release of chemical mediators which cause pain.  For this reason, a decrease in swelling will decrease
pain. 

By constricting blood vessels, ice treatments reduce swelling and decrease internal bleeding in the affected area.  Ice treatments also directly numb pain by blocking nerve impulses to the affected area. 

With chronic pain, chronic injuries or chronic conditions, ice treatments applied after an activity can decrease inflammation, swelling and pain.  It is important not to use an ice treatment prior to activity when dealing with a chronic injury or chronic pain.  When swelling is present in chronic conditions or chronic pain, ice treatments for short periods can be effective until the swelling decreases.  

Ice treatment is an effective way of preventing or reducing inflammation.  Never ice a chronic injury before exercise. 

Never apply ice treatments for longer than 20 minutes at a time and always make sure there is a barrier between the ice treatment and your skin.  As long as the skin temperature is allowed to return to normal, an acute injury can be iced numerous times per day for up to 72 hours.  Examples of ice treatments include a bag of ice, a bag of frozen peas or over the counter cold therapy wraps. 

With acute injuries, don’t forget to include elevation and compression along with your ice treatment.   

Heat Treatment:

Heat treatments are more effective for chronic injuries or chronic pain.  By stimulating blood flow to the area being treated, muscles, tendons and ligaments can be relaxed.  Examples of chronic injuries or chronic pain include, long-lasting muscle or joint pain, or overuse injuries.  In chronic conditions or chronic pain secondary to overuse injuries, heat treatments are effective if applied prior to the activity.  In general, heat should not be immediately applied after exercise – even with a chronic injury or chronic pain. 

After exercise or after performing an activity which contributes to the injury, ice treatment is a better choice – especially if inflammation or swelling is present.  In general, heat treatment should be reserved for chronic injuries in which inflammation or swelling is not present.  An exception to this is CRPS or RSD. 

Heat treatment should never be applied for more than 20 minutes at a time or when sleeping.  It is vital that a barrier be placed between the skin and the heat.  Examples of heat treatments include heating pads, over-the-counter hot packs, hot wet towels or paraffin wax. 

In summary:

1. Do not use heat treatment after an acute injury. 
2. Do not use heat treatments after exercise or overuse activity. 
3. Never use ice treatments or heat treatments when sleeping. 
4. Use ice treatments for recent injuries with swelling. 
5. Do not use ice treatments prior to exercise.
6. Do not use heat or ice treatments for longer than 20 minutes at a time. 
7. Allow the skin temperature to return to normal before repeating heat treatments or ice treatments.

If your symptoms do not improve within 48 hours, or if your pain is severe, consult with your doctor. 

Reference: 

The American Orthopedic Society for Sports Medicine.
http://SportsMedicine.about.com/cs/rehab/a/heatorcold.htm