If you've ever needed to recover from an athletic injury, you've probably used ice to reduce soreness and swelling. For decades, doctors and athletic trainers have recommended RICE - rest, ice, compression and elevation - to reduce the pain and inflammation of sprained ankles. Inflammation has been viewed as the enemy of recovery.
But what if that's not quite right? What if inflammation is an indication of recovery, and icing and other cold-based "cryotherapy" only delays it?
Icing, it turns out, is like flossing: an ingrained practice that seems practical but is not strongly supported by clinical evidence. The oldest justifications for icing, dating to the 1970s, have melted under scientific scrutiny, some cryotherapy researchers say, and most scientific studies on icing haven't provided the solid results that would justify its popularity. This is true, they say, both for icing for daily recovery and for an injury.
For example, a 2008 meta-analysis published in the Journal of Emergency Medicine, which looked at multiple studies on cold therapy's effect on acute soft tissue injuries, concluded there is "insufficient evidence to suggest that cryotherapy improves clinical outcome in the management of soft tissue injuries." Similarly, a 2012 paper published in the Journal of Athletic Training, which reviewed multiple, peer-reviewed studies, noted that the practice of using ice to treat sprained ankles "is based largely on anecdotal evidence" and that "evidence from [randomized controlled trials] to support the use of ice in the treatment of acute ankle sprains is limited."
Moreover, according to these papers and cryotherapy experts, the studies that have shown positive results from icing often have been plagued by shortcomings such as small sample sizes, irrelevant measurements and statistically insignificant results.
Even the doctor who coined RICE no longer promotes it. "It's perfectly fine to ice if you want, but realize it's delaying healing," Gabe Mirkin said, "[Icing] is not going to change anything in the long term."
Instead of icing to reduce inflammation, athletes might be better off letting it run its course. Better yet, get moving again, Mirkin said: "Don't increase your pain, but you want to move as soon as you can."
Athlete and journalist Christie Aschwanden feels a bit vindicated by the research. Despite her experience as a champion cyclist and professional cross-country skier, the use of ice, whether to recover from a hard workout or a rolled ankle, has never appealed to her.
"I used to have a teammate who was really, really devoted to ice baths," Aschwanden said. "She would fill our hotel bathtub with ice and then go sit in it. I tried it a couple times, but it was really painful. The discomfort and unpleasantness of it canceled out whatever benefits there were." Now, she said, after researching the issue, "I know there probably weren't any benefits."
Today, Aschwanden is a Colorado-based science writer for the data-driven website FiveThirtyEight and the author of "Good to Go," a new book on the science of recovery in sports. In one chapter, she examined ice packs, baths and massages and concluded that these cryotherapies are "not an evidence-based practice, in the sense that they've been shown to be helpful," she said.
The experts she cites in her book believe the justifications given for using ice - to reduce swelling and inflammation - aren't just lacking in evidence but could be counterproductive. "There's this idea out there that inflammation is terrible, and you want to reduce it," Aschwanden said. "But the inflammatory process is how your body recovers from exercise, and rebuilds and recuperates."
Immediately after tissue damage, cells send out a chemical distress signal that is answered by several types of white blood cells, which arrive on the scene and trigger inflammation as they go about their work attacking pathogens and cleaning up and repairing the damaged cells.
"If done for too long, icing can have a [negative] effect on regeneration," said UCLA professor James Tidball, who researches the immune system's role in muscle injury. In other words, by using ice to try to lessen inflammation, which is the immune system response to injury, you could also be reducing the activity of the cells that are promoting repair.
This isn't to say cryotherapy has no physiological effect. Icing to numb something definitely works, and "icing is the safest pain medicine we have," Mirkin said. Ice may also help people get a damaged area moving again. "If you have an injury, the muscles around it switch off," limiting mobility, said Chris Bleakley, a professor of physical therapy at High Point University in North Carolina who has studied icing. "Ice helps to switch those muscles back on again."
Some experts and research organizations who acknowledge the lack of high-quality data in support of ice nevertheless maintain that it's an important tool for athletes. The National Athletic Trainers' Association and the National Institutes of Health both recommend icing for sports injuries. And some point out that the lack of evidence cuts both ways. "We don't have a lot of evidence that ice doesn't work," said Mark Merrick, director of athletic training at Ohio State University. "We don't have a lot of good evidence at all. We have an incomplete view that limits how well we can draw conclusions."
Though she's in favor of evidence-based practices, Aschwanden won't be stealing people's ice packs or dragging them out of ice baths. And though a particular recovery method might not be clinically proven, a person's strongly held belief in it can enhance the placebo effect, she said, which actually does help in recovery.
In the book, Aschwanden describes an encounter with a friend (an icer) who inquired about its effectiveness. "What would you say if I told you it didn't help?" Aschwanden replied.
"I wouldn't believe you," the friend said.
"She wasn't dismissing me, like I'm not credible source on this," Aschwanden said. "She was just like, 'I know it works for me.' I think for a lot of this stuff, it really comes down to that. People have their personal experiences and those can be very convincing."
- - - Han is a science journalist based in Brooklyn.