How long should you ice an injury and why?

Scott D. Martin, MD
Orthopedic Surgery
Cold numbs pain and reduces swelling by constricting blood vessels. After surgery or injury, wrap an ice pack in a cloth and apply for 20 minutes, remove for 20 minutes, reapply for 20 minutes, and so on. To prevent frostbite, do not apply ice directly to the skin. Your source for cold can be as simple as a bag of frozen peas wrapped in a towel, but you can also buy easy-to-secure neoprene wraps with pockets for gel packs that you keep in the freezer. Most elaborate are electric "continuous-flow cold therapy" devices that deliver cold through pads shaped for different joints; your doctor or physical therapist may recommend such a device after surgery.

Ice helps knee injuries of all types. For hip injuries, cold can't penetrate deep into the hip joint itself, but it is still effective for hip pain stemming from problems closer to the surface, such as trochanteric bursitis (results from a single hard fall on your hip or the accumulation of minor stresses).

After injury, use ice alone for 24 to 48 hours. After that, you can continue using ice, switch to heat, or alternate. Ice increases stiffness, while heat helps restore and maintain flexibility. You may find it beneficial to use warmth before stretching and other exercise, following with ice afterward to minimize swelling. You can give yourself an ice rub by freezing water in a paper cup. Peel back the paper and cover the ice end with a cloth before applying to the area.

It is important to ice an injury as soon as possible in order to reduce swelling and pain.  While swelling is the first phase of healing, it also reduces motion and causes pain.  Ice is used to reduce this cycle. Ice from the freezer can be used on the skin 20 minutes at a time for most body parts (chemical ice packs may need a barrier such as a towel between the skin and the pack).  Four stages of cold are felt during this time: cold, ache, burn and numbness.  You can perform this treatment 20 minutes on- an hour off, as long as the swelling persists.  For smaller areas such as fingers and wrists you may go through the cold cycle sooner and only need to ice for about 10 minutes or so instead.

Yusuf Boyd, NASM Elite Trainer
Athletic Training
You should ice injuries for 20 minutes and allow at least 1 hour before icing again. The reason for icing is to decrease inflammation and/or pain in the affected area. The way it works is the ice lowers body temperature around the affected area, decreasing blood flow which in turn helps to reduce swelling.  After icing, the body naturally rewarms itself and as the blood flow increases inflammation is slowly reduced. You can repeat this cycle as often as possible during the first 48 hours for better results. You should continue the icing process past the first 48 hours until swelling and pain have diminished.
Aaron Nelson
Sports Medicine
You should ice for 20 minutes at a time and you can ice several times a day, depending on the severity of the injury, the amount of pain and the amount of swelling. You should wait at least 1 hour between ice treatments (starting when you take off the ice until you reapply the ice). If you are icing an area with less tissue, such as the hands and feet, you can ice for 10-15 minutes. Also, do not ice more than 10-12 minutes at a time in areas where a nerve is superficial or overly sensitive. Such areas include behind and the outer backside of the knee and the medial aspect of the elbow. Icing a "nerve" area too long can cause the nerve to freeze and decrease movement function and possibly cause long term damage. Ice is used to decrease pain and swelling and should be continued past the 48-72 hour window if swelling/pain persists. 
Dr. Michael Roizen, MD
Internal Medicine
You should ice an injury for 48 hours after it occurs because of the swelling (and for the sympathy you might get, of course). While swelling indicates an increased fluid or blood deposits in the area, it slows down recovery from the injury as the swelling from fluid makes joints stiffer and more painful, which in turn makes them weaker. Ice reduces the swelling-and pain.

After that 48-hour period, you use ice to generate heat (when you take the ice away it heats up) or heat alone on the injury to warm it up. The heat loosens up the joint or muscle, giving you more flexibility and allowing you to move it more freely during rehabilitation.
YOU: The Owner's Manual, Updated and Expanded Edition: An Insider's Guide to the Body that Will Make You Healthier and Younger

More About this Book

YOU: The Owner's Manual, Updated and Expanded Edition: An Insider's Guide to the Body that Will Make You Healthier and Younger

Between your full-length mirror and high-school biology class, you probably think you know a lot about the human body. While it's true that we live in an age when we're as obsessed with our bodies as...

Continue Learning about Bone & Joint Injuries

Bone & Joint Injuries

Bone & Joint Injuries

Often caused by falls, trauma, or injury, bone and joint injuries can sometimes be serious enough to require surgery. A broken bone can occasionally puncture your skin, causing intense pain. If you suspect that you have a broken b...

one, you will need medical treatment right away. In serious cases, pins, screws, and plates are placed into the body to stabilize the bone and help it heal. Joints connect our bones, and joint injuries can often occur in the elbows and knees. To reduce your risk of joint injury, stay healthy. Staying at a healthy weight and keeping your muscles strong and fit reduces the wear and tear on your joints.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.