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One of the most common questions that physiotherapists get asked is whether to apply ice or heat to an injury. Typically, you would apply ice to an acute injury and heat to a chronic injury. Unfortunately, many people are unaware of the differences between acute and chronic injuries so they tend to self-treat with the application that feels the best at the time. A good understanding between acute and chronic conditions is critical when faced with an injury.

An acute injury refers to one in which there has been a traumatic incident, such as a twisting motion, fall, or sprain. When an acute injury occurs the area is typically hot, swollen, inflamed and red in colour and ice should be applied as soon as possible. Chronic injuries usually do not present with a sudden onset. Instead they tend to worsen over a period of weeks or months. These types of injuries typically present with stiffness, tight muscles, and muscle spasm. Chronic injuries are best treated with the use of heat.

How does heat and ice help to resolve an injury?

Heat increases circulation by opening up blood vessels (vasodilation), relaxes muscles, improves elasticity (flexibility) of tissues, and relieves pain. Ice decreases circulation by narrowing blood vessels (vasoconstriction), decreases swelling, inflammation, and muscle spasms, and relieves pain. 

How to apply heat and ice?

Ice can be applied in many forms. I often suggest to patients to use a package of frozen peas or a wheat bag that can be placed in the freezer. Both of these mold well to affected areas.  Ice should not be applied directly to the skin. Instead, ensure that you place a towel between the ice and the skin. The ice should be applied for no more than 10 to 20 minutes every 1 to 2 hours. Examine your skin 5 minutes after the application. It is normal for skin to turn slightly red, however, remove the ice if excessive redness or discomfort occur.

The best type of heat to apply for chronic conditions is a moist heat. Your heat pack or hot water bottle should be wrapped in a damp towel. The moisture will allow for the heat to penetrate deeper into the underlying tissues and muscles. The heat should not be applied for  more than 20 minutes and the skin should be examined after 5 minutes to check for excessive redness and swelling.  If any of these are present the heat should be removed  immediately. Remember that excessive heat can lead to burns of the skin.

When to avoid the use of heat or ice....

Avoid both ice and heat when you have a severe circulatory condition, lack of sensation, are taking medications that may alter consciousness. Diseases such as  cancer in the area would also eliminate treatment with either ice or heat.  Avoid ice if you have anemia (decreased number of red blood cells), Raynaud's Disease (narrowing of blood vessels causing poor circulation), severe high blood pressure, or diabetes with accompanying circulation problems.  Avoid heat if you have internal bleeding, if the area is red and inflamed, have an open wound or infection, or have a skin disease.

When in doubt please consult with your physiotherapist. It is important to apply the most appropriate treatment for your injury to ensure the fastest recovery possible.