An Injury Primer: When to Heat It, When to Ice It


When you're faced with a sports-related injury, half of your friends will be adamant that ice is the only way to treat it. The other half will tell you that heat is the way to go. The problem is that most of your friends are idiots. So, which of your idiot friends are you supposed to listen to?

Probably none of them. While every injury and body is different, there are some general guidelines that should help you make the right call. We spoke to Dr. Sameer Dixit, MD, primary care sports medicine physician at the Johns Hopkins University School of Medicine for some advice on when you want to heat things up, and when you need to cool them down.

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When to Use Ice

“Very generally, for acute injuries within the first 48-72 hours, we recommend ice,” said Dr. Dixit. “Ice can help with swelling in these situations.” It's important to limit swelling when possible, because in addition to limiting mobility it can cause a lot of pain and general discomfort. “Ice tends to constrict blood vessels thus decreasing swelling,” says Dixit.

Ice can serve a secondary but also important function: It soothes acute pain. Cold temperatures cause numbness in living tissue. Strategic application of ice can ease your pain when it's at its worst. To prevent injury—an extreme example would be frostbite, which can actually cause skin and muscle tissue to die—it's recommended that you don't apply ice directly to the skin, and that you not use it for more than ten minutes at a time without taking a break.

When to Use Heat

“Heat is generally more helpful for issues that have occurred over time,” says Dr. Dixit. In other words, it's more likely to be helpful for chronic, reoccurring injuries, and “tightness if it is not related to swelling.” While ice constricts the blood vessels, heat tends to dilate them, increasing blood flow. That's why you generally don't want to use heat if there's swelling. You don't want to increase blood flow to an area that's already overloaded with blood.

Heat is more useful in instances of stiffness (again, when not related to swelling) when mobility and/or range of motion is somewhat limited. These conditions are often, but not always, caused or exacerbated by insufficient blood flow. In those cases, the judicious application of heat may provide some relief of these symptoms and promote healing.

Naturally, too much heat is another good way to damage your skin (ever heard of something called “burning?"), so similar to ice, it's best to cycle the application of heat on and off, though you can generally go for periods up to 20 minutes up to half an hour (think jacuzzis). If your skin becomes red, inflamed, or painful, stop and use a lower temperature for a shorter amount of time.

Use Cases

Pop quiz, hotshot. Let's take a look at a few quick examples of when you might use each.

Question 1. You're walking down the street and you see a clown car filled with 2-3 clowns, tops, driving past you. As you turn to watch them go by, looking for additional clowns, you trip over a toy poodle and spain your ankle. What do you use?

  • Answer: Ice. If you've sprained your ankle it's all but guaranteed to swell up in a hurry. You want to get ice on it as fast as you can. Yes, it will stiffen later on, but remember, heat generally makes swelling worse.

Question 2. You were a minor league pitcher with a promising career ahead of you. Then, one day, an unscrupulous scout suggested you try a new and highly experimental style of pitching, promising to take you to the bigs if you dialed it in. Over the years, your rotator cuff went south on you and you never threw faster than 75 MPH again. Ten years later, your shoulder still aches when it rains.

  • Answer: Heat. The kind of stiffness that comes from old injuries is one that heat often works well for. Maybe it never quite healed correctly, and the muscles and tendons never regained their former elasticity. Heat may allow those tight muscle fibers to relax a little, if only for a while.

Question 3. You're in the back yard, helping your 10-year-old niece with her batting technique, gently tossing her a hardball and giving her pointers. On your first pitch she rockets a line drive directly into your ribcage. You try not to cry in front of her. You fail.

  • Answer: Ice. You're in for a bruise my friend. Icing it immediately will not only decrease the pain (which may be considerable) but it can limit the inflammation and formation of the bruising, making at least not look as bad as it feels.

Question 4. You're out swimming in the bay, chasing seals and getting in the way of motorboats (both bad ideas). Suddenly, you feel your calf seize up. You can actually feel part of the muscle twist itself into a knot. You howl in pain and dog-paddle back to shore. You try to walk on it, but your leg has never felt so tight in your life.

  • Answer: Ice. Trick question! Yes, a muscle cramp is a form of extreme tightness which might make you think that heat is the way to go. After all, heat promotes relaxation, right? While that's often true, a muscle cramp is still an acute injury, and it's still liable to swell up after the muscle goes back to its normal shape. “If you watch a football game, when a player cramps, the athletic trainers are often applying ice locally,” says Dr. Dixit.

Question 5. Both of your parents began developing arthritis in their early forties, and now here you are, just 32 years old, and every time you stand up your knees sound like Jiffy-Pop with the burner on high. You could have been a contender.

  • Answer: Heat. Again, for conditions which have accumulated over time and which manifest themselves as stiffness, heat is typically the way to go. It will help boost blood flow and promote better elasticity in the muscle and connective tissue. This may manifest as a feeling of somewhat relieved “pressure” in your joints.

Caveats and Conclusions

While Dr. Dixit was happy to give these general principles, he stressed that there are no hard and fast rules you can use for every situation. “Always go see a doctor if you have any concerns,” he said. “None of this replaces an evaluation by a physician.”

He said that treatment really depends on number of variables including (but not limited to):

  • Stage of injury/disease
  • Location of injury
  • General health/medical status of athlete
  • Patient preference (patients may be better with one versus the other, in the same manner Tylenol may work better than ibuprofen for some people)

In other words, there are no hard and fast rules here. Talk to a doctor whenever you're in doubt, and listen to your body. If it's saying, “Heat will really make this feel better,” maybe it will. But in general, especially in severe cases, go with the advice of a medical professional. And be safe out there.