Hot or Cold Therapy for a Sports Injury—When to Use Each

Ice your knee. Apply heat to your back. When you’re in pain from a sports injury, you want to find the most effective means to relieve the pain, calm the symptoms and get you back in action. Both cold and heat can be effective for doing that, but not at the same time. Here’s how to know which one is best to use for your injury and when.

What Type of Injury Do You Have?

The type of treatment needed depends on the type of injury you have. Not if it’s your ankle or elbow, but whether the injury is acute or chronic. An acute injury is one that occurred in the last 48 hours. In athletes, this usually results from a fall or collision. A chronic injury is one that develops slowly, usually through overuse or because a previous injury has not healed properly. Think of how you may feel knee pain when you run more than 5 miles, ever since you had a bout of tendinitis. Chronic pain might not make you inactive, but it is nagging and bothersome.

How Cold Therapy Helps an Injury

Your body’s natural response to an injury is inflammation. The area that has been hurt can be red, sensitive or inflamed. This happens when damaged blood vessels expand. Ice helps restrict the blood vessels, which decreases swelling and pain. Ice therapy is most effective when applied early and frequently during the first 48 hours after an acute injury. Additionally, ice can be used on a chronic injury after a flare up, but otherwise should not be used for a chronic injury because it can increase stiffness.

How Heat Therapy Helps an Injury

Heat can be used for chronic injuries, particularly muscle strains and pulls, stiff joints and arthritis. While ice constricts the blood vessels, heat opens the blood vessels so more oxygenated blood can get to the injured area to speed healing. Heat also can be applied several days after an acute injury once the swelling has gone down.

Heat also can be used before exercise, to increase flexibility and range of motion. However, after exercise, ice is still recommended as the preferred treatment, even for chronic injuries, because it decreases swelling and pain.

Guidelines for Using Ice

• Use an ice bag with cubed ice or an ice pack.
• Do not apply the ice bag directly to your skin—the ice can damage tissue. Instead, wrap a thin towel around the ice for protection before placing the ice on your skin.
• Use the ice pack in 20-minute intervals, removing the ice pack for at least 10 minutes after each interval.
• Do not use ice in areas where you have a circulation problem.

Guidelines for Using Heat

• Use microwave heat packs, hot water bottles or muscle rubs for heat.
• If using a heat pack or hot water bottle, use for 20 minute intervals.
• Do not fall asleep on a heating pad—the heat can damage skin.
• Heat is not recommended for everyone: those with diabetes, open wounds or stitches should not use heat because it can increase bleeding.

Using Cold and Heat

A combination of cold and heat can help a freshly injured muscle, such as a sprain. The ice helps reduce the swelling, and the heat addresses pain and healing.

The key takeaways are to determine if an injury is acute or chronic, if you’ve just exercised or are getting ready to, and if you’re using the therapy to treat an ongoing injury. With these answers, you’ll know if ice or heat is best.