It's a no-brainer for anything you've hurt: Whatever it is, wherever it is, put an ice pack on it. From bruises on up to sprains and muscle pulls and worse, by-the-book treatment, whether by a professional or by the athlete herself, is to check off four basics: Rest, Ice, Compression, Elevation. (Or, you know, at least strap on a bag of frozen peas before resuming your workout.)
But now some critics are saying ice isn't the best thing for minor injuries, that it's not just overused but possibly harmful, because you're countering your body's own reaction, which is to ramp up inflammation and warmth. Could they be right? Is RICE a mistake best forgotten?

What ice is supposed to be for

Just to clear up confusion here, since some of us have a hard time remembering when to use ice or heat on an injury, the standard practice (which, of course, varies depending on who you ask) is to use ice in the first few days after an acute injury, to reduce inflammation. Ice dulls pain, and can counteract swelling. Many athletes like to pop ibuprofen or other anti-inflammatories during this time, for the same reason. After those first 48 hours or so, most trainers will tell you to back off the ice and start using heat to encourage healing. Important PSA here: No matter how good the ice feels, don't keep it on forever, and use a towel between the ice pack and your skin. People do get frostbite from enthusiastic icing, and of all the ways to get frostbite, that is probably the stupidest.

So we're stopping inflammation. Inflammation has a bad rap, and not just for acute injury. It's what powers autoimmune disorders, and chronic inflammation is considered to be a bad guy in the development of heart disease and cancer. And then you sprain your ankle and it starts to hurt and swell? Grab the ice! Down with inflammation!

But inflammation is also a tool your body uses to clean up infections and repair damaged tissue. When you tweak your knee or drop a weight on your toe, cells start sending mayday signals that cue blood vessels to dilate and blood flow to increase. What's more, it makes the blood vessels in the injured area leaky, so fluid is squeezed into the injured area, and with that fluid comes antibodies and white blood cells. In other words, when your joint begins to swell, you know the repair crew has arrived.

The backlash

Happily, there's a trend where sports medicine people are re-evaluating their guidelines to make sure they are "evidence based." Evidence-based practice means that you recommend treatments not based on "we've always done it this way" but instead, because scientific studies clearly show that it works.

Although advice to apply ice to injuries is widespread, a study of different groups' guidelines found that they weren't rigorously evidence-based, and that they were all over the board in terms of recommendations for how much to ice and how long—a major red flag.

Gabe Mirkin, the man who coined the RICE acronym so many of us swear by (Rest, Ice, Compression, Elevation) has recently, and publicly, reversed his position. "Anything that reduces inflammation also delays healing," he writes, including ibuprofen and ice. (He also advocates replacing rest with gentle movement, but he's still cool with compression and elevation.) He cites a 2004 review of the evidence for cryotherapy (which is the scientific word for "putting ice on injuries") that finds, in short, that there is very little evidence for cryotherapy.

According to that review, there have been no randomized studies on whether ice helps muscle bruises or pulls, and only a handful on ankle sprains (which conclude that ice and compression together seem to help, but it's hard to say if the ice is a necessary part of that). Meanwhile, it's actually really hard to do randomized trials with ice, because of that tendency to pile on the ice after injury. In one study, 60 percent of the "no ice" group had already self-iced by the time they sought treatment.

Many of those studies looked at short-term outcomes like whether ice reduced swelling and pain, but a more important question is whether ice helps or hurts in total healing and recovery time. A review of how soon athletes can return to play found that ice "may have a positive effect" but, as before, the studies behind that conclusion weren't very good quality.

The bottom line

This is not to say that ice is useless. It does relieve pain, which can be helpful. Personally though, I find Mirkin's arguments pretty convincing. After all, if inflammation is necessary for healing, trying to combat that inflammation may backfire and prolong the recovery period.

But the lack of evidence in favor of ice doesn't tell us that ice is harmful; it just means that the science isn't ready to help us decide. The good news is that if ice was really really bad for you, we would have noticed by now. Likewise, if ice was the angelic savior of injured tissue, that fact might shine through even shoddily designed experiments.

What's more, ice is probably not an all-or-none proposition. Part of the low quality of the studies was that they used different amounts, durations, and timings, so that it was impossible to compare them. Is it possible that a little ice is better than a lot? That there's a sweet spot a few days after injury? That there are nuances that studies haven't picked up on yet, but that might turn out to make a big difference in recovery? Definitely possible.

In the meantime, ice is probably helpful for reducing pain or if you have really extreme swelling (although be careful if you're intending to apply ice and then jump back into your sport—it may affect your coordination). But will it hurt your recovery in the long term? That's a big fat maybe.