How Long Should You Ice An Injury

Photo of a woman with ice on her knee.
Know when to stop using ice by listening to your symptoms. PhotoAlto/Odilon Dimier/Getty Images

Question: How Long Should You Ice An Injury

After injuring my knee, how long should I leave an ice pack on it?

Answer: Ice should be applied to an acute (newly sustained) injury for only 5 to 10 minutes at a time. Any longer than this could result in tissue damage to the skin by frostbite or lack of blood flow. You can apply ice several times per day.

What Does Ice Do?

When you injure a body part, your body goes through the inflammatory process to help heal the tissue.

Hallmarks of inflammation include:

  • Increased tissue temperature
  • Redness
  • Pain
  • Swelling

And guess what? Your body is really good at sending blood and cells to an injured body part to heal it. Almost too good. That's why we use ice to control the swelling and pain.

When ice is applied to your body, it causes vasodilation, and this limits blood flow to a specific body part. That limited circulation helps to keep swelling down. The ice also helps to decrease painful signals that you may be feeling after your injury.

How Do I Know When It Is Time To Stop Icing?

The 10 minute ice time is really just a general guideline. What if you just can't tolerate 10 minutes of icing on an injured body part? Is there another way to know when to stop icing?

There is. You can use the CBAN method of icing. CBAN is an acronym that stands for cold, burn, ache, numb. Those are the sensations you should feel when applying ice to your injured body part.

When you first put ice on, it should feel cold.After keeping ice in place on your injured body part for a few minutes, you should feel a slight burning sensation. This should only last few a few minutes, and then it will be replaced by an ache.

After the aching, you will notice that the ice is making your skin feel numb.

When you get to the numb feeling, it is time to remove the ice, regardless of the amount of time you have placed the ice on your body. The CBAN acronym simply uses your own body's sensations to tell you when to remove the ice.

Is Ice Really Necessary?

Icing an injury has been the conventional wisdom for some time, but recent research indicates that it may not be absolutely necessary. Some studies even indicate that the reduced blood flow to injured tissues delays the healing process. After all, your body has been healing itself for quite some time. Why all the sudden should we control that process?

Ice can help make your injury feel better, so many experts recommend using ice for only a short period of time. It may be best to keep the ice on for 5 minutes, and then off for 30 minutes to restore normal blood flow. Bottom line: check in with your doctor, use the CBAN method, and keep your injured body part moving. (Using the P.O.L.I.C.E. principle is a good idea.)

Can I Make My Own Ice Pack?

If you don't have an ice pack or if your ice bag melts and then freezes again into a big block of ice, your icing won't be very effective.

You can make your own ice pack that you can refreeze again and again without it becoming a big ice block. Here's how:

  • Place ice cubes and a cup of water into a plastic bag.
  • Add a few tablespoons of rubbing alcohol.
  • Seal the bag. The alcohol will prevent the ice from forming a big block in the freezer.

Icing in recent years has been under scrutiny. Is it really effective? Is it necessary? One thing is for sure: it can help decrease your pain and make you feel good. When icing, use the CBAN method, keep the ice on for only 5 to 10 minutes, and keep your body part moving before and after icing. Checking with your PT is a good idea to learn exactly how to manage your injury.

Edited by Brett Sears, PT.

Khoshnevis, S. Et al.  Cold-induced vasoconstriction may persist long after cooling ends: an evaluation of multiple cryotherapy units. Knee Surg Sports Traumatol Arthrosc. 23 (9), Sept. 2015.

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