How Long Should You Ice an Injury?

A twisted ankle. A bent wrist. A wrenched back. We’ve all been there, groaning in agony after straining a joint or muscle — and an ice pack is usually one of the first things grabbed in search of relief.

Primary care sports medicine physician Anne Rex, DO, explains how long to ice an injury to maximize the benefits and minimize the risks.

Why icing helps an injury

When an injury occurs, it causes an inflammatory response in your body. “This response is part of the healing process, but it can be uncomfortable,” notes Dr. Rex. “Ice helps by halting inflammation.”

Applying cold to an injury:

• Reduces pain: Ice has an analgesic (pain-relieving) effect on an injury. The numbing effect of ice essentially reduces the pain input signals from the injury to your nerves.
• Decreases inflammation: Your body sends blood and inflammatory chemicals to the site of an injury, creating inflammation. Icing causes temporary changes in the blood vessels around the injury to reduce blood flow and lower inflammation and swelling.

How to ice an injury

Crushed ice or a frozen gel pack works best for icing because you can mold it around the injured body part, says Dr. Rex. If you don’t have that handy, a bag of frozen peas or carrots works well.

It’s always best to use a barrier such as a washcloth or a few layers of paper towels under any ice pack to protect your skin from the intensity of the cold.

Avoid icing areas that have:

• Any wound or break in the skin
• Blisters
• Burns

How long should you apply ice to an injury?

Recommendations for icing injuries often vary given the lack of research on treating common sprains and strains. In general, though, the maximum icing time shouldn’t extend past 20 minutes. In many cases, 10 to 15 minutes is fine.

What happens if you ice for more than 20 minutes? Basically, you start undermining the healing process — which isn’t exactly the goal.

“Anything over 20 minutes can cause reactive vasodilation, or widening of the blood vessels, as your body tries to make sure your tissues receive blood supply,” says Dr. Rex. “Vasodilation can undo some of the benefits of icing an injury, so it’s counterproductive to ice too long.”

Signs you’re icing for too long

Signs that it’s time to remove the ice pack include:

• Skin turning red or pale
• Itchy, prickly or tingly sensations

Taking an icing session too far could lead to a cold-induced injury on top of your original owie. “The biggest risk is frostbite, or the milder version, frostnip,” cautions Dr. Rex. “Nerve injury can be a side effect of icing too long.”

That’s why you should only ice when you’re awake, too. Falling asleep with an ice pack on could result in a cold-related injury.

Other factors when icing an injury

The appropriate amount of time to ice an injury also may vary based on:

• Cold tolerance. People with Raynaud’s syndrome and some autoimmune conditions don’t tolerate cold well. If this is you, don’t keep icing past your comfort level.
• Individual factors. Children, older people and smaller individuals are more prone to tissue damage from over-icing, so it’s best to err on the side of shorter icing times.
• Injury location. If the injury is in a sensitive area, like your groin, you may not be able to tolerate extended icing sessions.
• Nerve health. People with nerve damage may not feel the signs of over-icing. If you have neuropathy or another nerve condition, you may want to shorten your icing time to be safe.
• Size of the joint. A finger joint doesn’t have much tissue and is close to the skin’s surface. Finger injuries may require less than five minutes of icing. A deep hip injury, on the other hand, may need the full 20 minutes.
• Smoking status. Smoking causes cardiovascular changes that can reduce sensitivity to cold. People who smoke may be more prone to injury from icing too long.

When should you ice an injury?

You get the biggest benefit from icing if you start as soon as possible after the injury happens, Dr. Rex emphasizes. It’s OK to ice again, too, but space your 20-minute icing sessions at least one to two hours apart.

Keep icing off and on for two to four days if it seems to help, advises Dr. Rex. If swelling continues longer than that, consider going to urgent care or your healthcare provider. You may need X-rays to check for a fracture or other imaging tests to look for tears in connective tissue.