Do Ice Baths Work?
Long story short, they may reduce pain, but they don’t speed the healing process.
The following is an excerpt of Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery by Christie Aschwanden.
In the photo, LeBron James gives a look that’s a cross between a grimace and a snarl. The superstar forward then playing for the Los Angeles Lakers is submerged waist deep in a bathtub filled with ice cubes, and his powerful shoulders bulge as he holds his arms and hands up out of the frigid water. “Training camp ain’t nothing nice! #MyFaceTellItAll #ThisTubColdAsYouKnowWhat #StriveForGreatness,” reads the caption on the image, which James shared with his nearly 30 million Instagram followers. The message was clear: James wasn’t just training hard; he was recovering hard too.
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Training camp ain’t nothing nice! #MyFaceTellItAll #ThisTubColdAsYouKnowWhat #StriveForGreatness
Training camps like the one LeBron was attending that year can push athletes to utter exhaustion. This is by design—blocks of intense, multiple daily training sessions are intended to force athletes into a state of “supercompensation,” where the body adapts to stress by fortifying its resources to become faster, fitter, stronger.
The road to supercompensation is paved in pain, and icing is a popular (if counterintuitive) way of coping with the hurt. Although it’s painful at first, icing eventually numbs the affected areas and people swear it reduces soreness. The practice has been around for several generations, but the icing age really took hold in sporting circles around the time that physician Gabe Mirkin wrote about the familiar term RICE (Rest, Ice, Compression, Elevation) in his 1978 tome, The Sports Medicine Book. Mirkin didn’t invent the acronym or the sequence of actions, which had been mentioned in medical journals as early as 1906, but he helped popularize it within the sports medicine community. For twenty-five years, Mirkin hosted a syndicated call-in radio show about health and fitness, where he often mentioned RICE.
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Intended as a way to speed the body’s healing by shunting blood and inflammatory cells away from injured tissue, RICE became a standard treatment for sprains and strains, as well as for muscles that were sore from exertion. In the four decades since Mirkin first promoted RICE for sports injuries, icing has become standard advice for people suffering sprained joints, sore shoulders, and other orthopedic aches or injuries. Who hasn’t rolled an ankle and been told to put an ice pack on it? Today, ice packs have become as ubiquitous as aspirin—they’re a fixture in every athletic training facility and sold in drugstores throughout the country.
Cold baths and ice tubs have also become one of sport’s most popular recovery aids. Nearly every high school, college, and pro trainer’s room has at least one ice tub, and over the last ten or fifteen years they’ve become an essential postworkout ritual for athletes in every sport. One attraction is that icing is cheap and easy. With a few bags of ice and a bathtub or even a garbage can, any athlete can make a low-budget ice bath in a matter of minutes.
Icing aficionados can be found in nearly every sport. Marathon world record holder Paula Radcliffe helped popularize cold treatments among runners by attributing some of her success to the ice baths that became her habit. Surfer Kelly Slater is also a fan. In an Instagram photo, he appeared sitting in a metal tub filled with ice water, his arms levitating stiffly above the water, as if he’s on the verge of jumping out, and his lips puckered into an expression that screams, ouch! During NFL training camps, it’s typical to see whole teams of players shivering in tubs of ice. In the summer of 2016, an ESPN reporter tried some immersive journalism by interviewing Washington Redskins defensive lineman Chris Baker while the two sat in adjacent plastic tubs of ice water. And at one recent summer training session, ten Newcastle United soccer players were photographed crowded into a single inflatable kiddie pool filled with ice water. Even rock stars use ice baths. Madonna told Rolling Stone magazine that after her performances, which usually include hours of dancing, often in high-heeled shoes, she likes to take a ten-minute ice bath to recover. “It’s really painful when you get in, but it feels so good afterward,” she said.
That sense of triumph is earned—an ice bath hurts. You can’t ease into it, one toe at a time, because the natural reaction to this kind of cold is to recoil. Instead, you have to plunge in and submerge yourself before you have a chance to change your mind. The first few seconds you’re fighting your body’s impulse to get the hell out. After that, you’re just marinating in steady anguish. Toes throb and sting. Feet ache. Large muscles, like your calves and quads, tingle and burn, and if you have genitals that dip into the icy water, they might try to rush back up the inguinal canal. “A man in an ice bath will never get an erection,” said one expert who made me promise I wouldn’t name him.
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All this agony feeds into a culture of sport that idolizes grit and assumes that pain equates to gain. The fact that icing feels so excruciating almost surely adds to whatever effectiveness the technique might have. Scientists call this an active placebo effect—our natural inclination to believe that if a treatment is painful, it must be very effective. If it hurts, you assume it must be working, and this can influence your assessment of how much it helped.
The rationale behind recovery ice baths and cold tubs goes something like this: the cold stimulates your sympathetic nerve fibers, which react by signaling blood vessels in the area to constrict and send blood back to your core to protect your vital organs. This rush of blood away from the extremities reduces blood flow to the areas you’re icing and slows the metabolic processes in these regions, including the inflammatory response, and thus reduces any swelling that might otherwise happen. The pressure of the water may also provide some compression against your muscles and blood vessels, which could also slow swelling and inflammation. Finally, icing relieves pain by numbing sore areas, at least temporarily.
That icing might suppress inflammation was originally a selling point. But in recent years, Mirkin, popularizer of the RICE method, has come to think of this as a bug, not a feature. In a complete turnabout, he now denounces the icing methods he once championed. There’s no question that icing can reduce pain, at least temporarily, he told me, but it comes at a cost. “Anything that reduces your immune response will also delay muscle healing,” Mirkin says. “The message is that the cytokines of inflammation are blocked by icing—that’s been shown in several studies.” He now believes that instead of promoting healing and recovery, icing might actually impair it, and his change of heart came about largely because of one man.
Gary Reinl is a cold warrior. A slight man whose longish, graying hair is often topped with a baseball cap, Reinl has the fit, tanned look of a veteran marathoner. The Las Vegas–based personal trainer and entrepreneur has spent the past forty years working in the health and fitness industry. In that time, he’s created rehab programs for injured workers and developed a strength-building protocol that’s used in senior living facilities across the country. In the summer of 2016, he received a certificate of recognition commending him for outstanding achievement in support of the White House Medical Unit, and he’s consulted for professional golfers, tennis players, CrossFitters, and NFL, MLB, NBA, and NHL teams. He’s written books about postpregnancy fitness and fat loss, but his most recent title, Iced!, is a self-published opus on the futility of icing sports injuries and tired muscles—cause that has become his obsession.
Reinl is not a physician or a scientist or a coach. “I’m just a reporter trying to help people,” he says. His journey to becoming an icing skeptic began in the summer of 1971. He was about to start his senior year of high school, and he was on a mission: to break his school’s pull-up record. To succeed, he’d need to complete forty-two pull-ups from a dead hang. After some secret practice, he could do twenty-eight at a time, and so, confident that if he kept up his practice he could have the record beat by the end of the year, he announced to some friends that he intended to pursue the record. In the meantime, word of his plan got out and a rival announced that he could already do forty pull-ups and would try for the record too. “I was crushed,” Reinl wrote in Iced! He considered the other guy tougher and more muscular than himself, and so he abandoned his goal. Later that year, the two boys tried out for the Marine Physical Fitness Team. One of the events was a pull-up test, and Reinl watched as his opponent struggled to complete fifteen pull-ups. “I was sick to my stomach,” Reinl says. His blind faith in his rival’s boast had broken his dream.
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That, he says, was the last time he accepted an assertion without proof. “From that moment forward, I tried my best to do all that I could to identify and reject any unsubstantiated claims,” he wrote. Since then, Reinl has made a career of questioning conventional wisdom. He has argued, for instance, that women could feel better during pregnancy if they do some strength training, and that older adults could abandon their walkers and wheelchairs if they take up strength training.
His latest mission is simple—to convince people to stop using ice on sprained joints and sore muscles. He likes to mention the Museum of Questionable Medical Devices in St. Paul, Minnesota. “I won’t rest until the museum adds another ‘questionable medical device’ to the curators’ collection—the ice pack!” he says.
Over the years, he has worked with athletic teams, elite military squads, and coaches and trainers across the world. “The vast majority of people that I work with use ice—until they meet me,” he says. “The first question I ask everyone is: why are you using ice? What are you trying to do? Most people say, ‘to prevent inflammation,’” he says. “Well, why would you ever want to block or prevent inflammation? Without inflammation you won’t heal! That’s how your body regenerates!” His voice intensifies with impatience as he says this, struggling to conceal his frustration with the stupidity he’s calling out. “When you ice, you don’t block or prevent anything. All you do is slow things down so you don’t heal as quickly.”
In order to assess Reinl’s argument, it’s essential to understand what’s happening in the body after an intense bout of exercise. One of the most common (and painful) aftereffects of a hard training session is muscle soreness, particularly the phenomenon called delayed-onset muscle soreness, or DOMS, that left me cobbled after my first Garfield Grumble running race. The agony of DOMS normally maxes out about 24 to 72 hours after the exercise, and it’s most acute when you exercise your muscles in a way that they are under strain while they’re lengthening. These opposing forces tug at the muscles, producing microscopic tears in the muscle fibers.
Your body responds to this injury by mobilizing a cleanup crew to remove damaged tissues and rebuild the muscles. This process fortifies the muscles, making them stronger. The repair response is also why a repeat bout of muscle-damaging exercise produces less DOMS than the first—because your muscle has become stronger and more resilient in response to the initial bout.
The cleanup and repair process is essentially the inflammation process, and Reinl’s basic message is this: inflammation is your body’s way of healing, and the only thing that icing does is delay this healing response. And that’s true whether you’re icing an injury or the micro damage from a hard workout. You can think of these insults as akin to freeway traffic accidents. When there’s a wreck, you want the traffic flowing around it so that the ambulance and first responders can get to the crash site as quickly as possible. The same is true for an injured joint or sore muscle—you want the immune system to get to the site of the problem pronto, but icing shuts down blood flow and slows the immune system’s response, Reinl says. It’s like sending traffic off the highway and then closing the on-ramps so medics can’t get to the accident. Instead of speeding recovery, this approach just delays emergency crews from doing their jobs.
Whether you’re icing an injury to reduce swelling or cooling a sore muscle to tame inflammation, the approach won’t work, Reinl says, because icing merely slows blood flow to the area, it doesn’t halt it indefinitely. Once the icing stops and the blood flow returns to normal, whatever process you were trying to hinder will proceed again. The swelling will continue and the inflammation will start. The only thing you did was delay things. On this matter, Reinl managed to sway Mirkin, who wrote, in a foreword to Iced!, “Gary Reinl has done more than anyone else to show that cooling and immobilization delay recovery.”
People are often shocked by Reinl’s message, which in his animated telling can come across as a diatribe. But he’s got research behind him. “People will say I’m an idiot, but not a single person has pointed out a mistake. And you know if they could find something, they would and it would be all over the internet,” Reinl says.
Indeed, recent studies confirm Reinl’s hunch that rather than speeding recovery, icing or cooling could actually hinder it. A 2006 study compared the training effects of a cycling ergometer or handgrip exercise with or without a cold bath afterward. Participants did the same exercise on all limbs, but only one arm or leg was subjected to the ice bath. Over the course of four to six weeks of training, the cooled limbs made fewer performance improvements than their counterparts that were spared the cold plunge. Yes, ice can reduce the pain of swelling, but it doesn’t seem to expedite the healing.
Excerpted from Good to Go by Christie Aschwanden. Copyright © 2019 by Christie Aschwanden. Reprinted by permission of W. W. Norton & Company.
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About Christie Aschwanden
Christie Aschwanden is a science writer and author of Good To Go (Norton, 2019).