Should You Use Heat or Ice After an Injury?

Should You Use Heat or Ice After an Injury?

I have been a physical therapist for almost 30 years and this is still one of the most common questions that my patients have asked me over those three decades. Should I use heat or ice after an injury?

To decide whether you use heat or ice you have to know a little bit about how they both work with the body.

When you heat a body part you increase the tissue temperature. But what does that do and why is it important?

How heat affects the body:

Increasing tissue temperature causes a dilation or widening of the vessels (think of an elongated balloon slowly getting blown up) in and underneath the surface of the skin.

You essentially end up increasing blood flow to the area. This can be very beneficial when there is chronic (long-term) tension in a muscle. This could be when a muscle feels tight and due to excess tension or chronic pain resulting from decreased movement for prolonged periods or even overuse, the muscle or tissue ends up receiving less blood flow to that area.

Therefore in the case of chronic or long-term tension, heating the area brings blood to it and helps it relax (remember the vessels expand and essentially relax with heat; think about the typical American’s waistline after Thanksgiving dinner!)

But will heat fix the issue?

You probably can see why heat may help a chronically stressed muscle now. Increased blood flow to a tight muscle = decreased tension. This can result in a decreased pain response as well, but usually only temporarily. Because if you go back to doing what you did prior to adding the heat and don’t correct why the muscle was tight in the first place, it may feel better in the short term but not always in the long term. The pain often returns.

When muscles are constantly fighting against gravity and our poor postural position over time without much movement throughout the day muscles begin to tense up, get sore, feel tight or overstretched and blood flow through the muscle slows. Heat is your friend here and can bring temporary pain relief.

But when it comes to a brand new injury heat is often not your friend. And sometimes for up to six or even eight weeks after an initial injury heat alone may still not be a good option.

So, when should you ice an injury instead?

Ice is the preferred method directly following an injury and generally when swelling is present. Some exceptions apply but this is the general rule.

Icing an area results in constriction of the vessels in the skin and underneath the surface (think trying to fit into your jeans after a Thanksgiving dinner!) This constriction causes decreased flow of fluid to the injury or an absorption of fluid that is present which causes the swelling to decrease. By keeping this normal reaction to an injury under control with proper icing, elevation and often compression we can speed up the healing process.

Note: the body is not doing something wrong when it swells up after an injury. As a matter of fact, we need this reaction to begin our healing process. But too much of that good thing can be an issue over weeks after the injury. If the swelling is not addressed it will be more difficult for the body to heal and also more difficult for us to return to our activities due to lingering pain and potential instability.

The verdict: heat or ice?

Rule of thumb: Always ice an injury immediately after and as long as swelling and or pain remains. Make sure you rest the area affected, utilize compression if possible and elevate the injured area (if possible). Remember the acronym R.I.C.E.: Rest, Ice, Compression, Elevation.

In the days and weeks after the injury, a combination of heat and ice can be used.

Are there any exceptions?

If it is a joint injury like an ankle sprain for example, versus something like a pulled muscle, stick with ice until the swelling is gone. It’s rare that you would want to use heat directly over a joint if swelling persists. HOWEVER, if the muscle close to the joint affected is causing an issue or if a physical therapist or physician identifies “capsular” tightness in the joint, then heat to warm up the tissue around the joint followed by exercise and or massage of that area can be beneficial. But always end with ice after exercising the affected body part, especially in the six to eight weeks after an injury.

You definitely don’t want to add heat to an area if it is already red and inflamed. It’s already hot in part from increased blood flow and that heat is due to increased tissue temperature below the surface so you don’t want to heat it up more.

How long should you heat or ice an injury?

Ice and heat can both be applied for the same length of time i.e. between 10-20 minutes generally for it to be effective. Five to ten minutes over smaller areas like fingers or a wrist.

If it is a new injury, ice on and off every hour or two for twenty to thirty minutes and follow the R.I.C.E method. Do this for at least 48 hours or longer depending on the severity of the injury, the pain you are experiencing and what structure is effected.

So, in a nutshell remember:

  • Ice for any new injury, and or when there is still swelling present.
  • Never ice before exercise as you will numb your sensation to pain and may further injure yourself.
  • A combination of heat and ice can be beneficial if swelling is no longer present or only present after activity (and then you would ice).
  • Heat for chronic pain/stiffness of a muscle or joint to help increase blood flow to the area and increase tissue elasticity. This can be followed by stretching and massage and exercise for further relief and ending the session with ice.

Hope this helps!

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Guest post by Stacey Roberts PT, Naturopath
SMART Clinic

Stacey specializes in Sports Medicine, Women’s Health, Couples Fertility, and Nutrigenetics (Personalized nutrition and supplementation based on genetics review).



This information is not intended to treat, diagnose, cure, or prevent any disease. All material in this article is provided for educational purposes only. Always seek the advice of your physician or other qualified health care provider with any questions you have regarding a medical condition, and before undertaking any diet, exercise, or other health program.

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