Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery

by Christie Aschwanden

A significant result from a small study is more likely to be a false positive than a significant result from a large study. In a paper published in 2012, psychologists calculated the likelihood of obtaining statistically significant results and showed that it’s easier to meet this goal by doing five small studies with twenty participants each rather than one study with one hundred people.

Following strenuous strength training, the exercised muscle’s strength is typically diminished for a period of up to 60 hours while the muscle rebuilds and repairs itself.

The marketing around sports drinks rests on a fundamental, seemingly scientific premise—that even minor dehydration raises health risks and hinders athletic performance and recovery—but this idea appears overstated. It’s more marketing than science.

Although hydration guidelines instruct athletes to drink according to how much weight they’re losing through sweat and respiration, “drinking according to the dictate of thirst throughout a marathon seems to confer no major disadvantage over drinking to replace all fluid losses, and there is no evidence that full fluid replacement is superior to drinking to thirst,” the study’s authors wrote.

There’s never been a case of a runner dying of dehydration on a marathon course, but since 1993, at least five marathoners have died from hyponatremia they developed during a race.

I’ve often noticed that water tastes especially delicious when I’m thirsty, and Knepper says that’s not my imagination, but the work of receptors in the back of the throat that can influence perception.

There’s surely a period where your body needs protein to repair and build after a muscle-straining workout, particularly something like a max session in the weight room, a CrossFit WOD (workout of the day), or a high-intensity interval session. But it’s not so much an anabolic window, Schoenfeld says, “it’s an anabolic barn door.” As long as you eat breakfast, lunch, and dinner, it’s almost impossible not to get through.

How much protein do you need? For a while, studies seemed to suggest that the benefits of postexercise protein topped out at about 20 grams, but more recent research implies that some athletes with a lot of muscle mass may benefit from something more like 40 grams, says James Betts, a sports nutrition researcher at the University of Bath. What’s the best number? Researchers are still debating the answer to that question, and the best way to resolve it is with more data.

We’re programmed to maintain homeostasis—a physiological state of equilibrium—even when conditions are less than optimal. Which means that it’s important to get the big picture right, but fixating on the smallest details won’t necessarily yield much payoff.

When your muscles are hungry for fuel, they don’t care where the energy comes from, says Brent Ruby, the University of Montana scientist who supervised the cyclists study, done by his then-graduate student Michael Cramer. The fast food in this experiment may not represent the healthiest everyday food choices, but neither are those engineered recovery foods, which are highly processed and laden with additives, he says. Regardless, any of these foods work. “The muscle could care less. If you’re dumping in carbohydrates, the muscle is going to be satisfied.”

Several studies have suggested that taking a high dose of antioxidants might blunt the training adaptation to exercise, although Jeukendrup cautions that the relationship between antioxidants and adaptation is still being worked out, and not all studies have found that antioxidants hinder adaptations (or even reduce inflammation).

Unless you have some need to expedite recovery, like you’re in the Tour de France and you have to do another race the next day, the exact timing of your postexercise nutrition isn’t do or die. “You can just go have a regular meal and you’ll be all right,” Betts says.

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.

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.”

Really, who doesn’t enjoy a massage? It feels really good, but despite all the love that athletes feel toward having their muscles rubbed and pressed, “There are very few evidence-based benefits for massage,” says Paul Ingraham, a massage therapist, former editor at ScienceBasedMedicine.org, and publisher of PainScience.com.

Her research with Butterfield has shown that massaging a muscle can produce changes in immune cell markers, and these changes seem to vary depending on how hard and deep the massage goes. “How that changes pain, we don’t know,” she says.

Butterfield’s studies on massage have turned up intriguing evidence that massage performed shortly after exercise may increase protein synthesis in the muscle, at least in rats. “We think it’s the mechanical signal that the massage gives. We’re giving the cell a signal to react differently.” His results have been repeated in animal studies, but await confirmation in humans. If this happens in people too, it might mean that massage could help muscles heal from exercise-induced damage by promoting repairs via protein synthesis, but that idea remains theoretical and unproven as of yet.

He says it’s still an unproven hypothesis, but it seems possible that very deep massage can cause tiny tears or injuries to the muscles that release myoglobin and lead to “rhabdo.”

“We know that fascia has the physiological characteristics to be a pain generator,” Wilke says. When researchers injected a hypertonic salt into the fascia (a harmless way to inflict pain in the lab), people rated it as more painful than when the injection was made into the muscle.4 This could well be the reason that it can hurt to use a foam roller or one of the countless other self-massage devices that have become popular.

“The tissue can stick together because fascia is not only a sheath around the muscles, it also has three or four layers and between the layers we have hyaluronic acid—the same fluid that’s in joint capsules,” Wilke says. The hyaluronic acid reduces friction to allow the layers of fascia to glide and move smoothly. If you don’t move, it’s possible that the fascia could become sticky and restrict movement, and if this theory is correct, it might explain why some people wake up in the morning feeling stiff, Wilke says. One idea behind pressing and massaging a muscle group with a foam roller or similar device is that it works out adhesions between layers of fascia. “This is a very very plausible theory, but it has not been proven so far,” Wilke says.

A 2017 study found that foam rolling the back of one leg also increased ankle flexibility in the other one.6 Research by David Behm at Memorial University of Newfoundland has similarly suggested that foam rolling, say, the right calf muscle decreases the pain threshold in the left calf too.

What’s the evidence that wearing these things will help me recover? The studies on compression clothing are mixed. Shona Halson, the Australian recovery expert, said that “overall, if you look at the majority of studies to date, there seem to be small positive effects from compression garments for both performance and recovery.” A 2013 meta-analysis found that compression clothing moderately reduced delayed-onset muscle soreness, as well as aiding the recovery of muscle function after exercise.9 A 2017 review found similar small benefits.10 Morgan said that there’s a psychological component at play here too. Some people really like the way compression garments feel. During exercise, they can reduce vibration in the muscle, and afterward they can make muscles feel that they’re getting a hug.

After one particularly rough journey where my race skis went MIA, I was tired, hangry, and on the verge of a meltdown. Our team director took me aside for some words of advice. Look, he said. These hassles are just part of the job. You want to be a ski racer? Then learn to deal with it. You can waste all your energy getting pissed at the airline, or you can accept that this stuff is going to happen and save your emotional energy for the race. He was right. I couldn’t change what was happening, but I could change the way I responded. That shift in attitude instantly reduced my stress levels.

It may sound counterintuitive, but he says that rather than turning away from a source of stress you can’t eliminate, it’s more effective to turn your attention toward it. “It really boils down to one thing—if there are thoughts that you don’t dare to have, you’re stuck with them, that’s the bottom line,” he says. “It’s accepting [the stressor], and accepting it just as it is.”

We’re primed to push through the pain and do another mile or one more set. We celebrate “streakers” who run every day for years. But if your body isn’t recovering from and adapting to those runs, then you’re just logging junk miles that are wearing you down instead of building you up. I don’t mind celebrating those impressive people who keep their exercise streaks alive, but maybe we should lionize athletes who’ve mastered the art of resting too.

Insofar as there exists any magical secret for recovery, sleep is it.

Stage three is the deepest stage, which is also associated with memory processing and is when the body releases substances like testosterone and growth hormones to push tissue repair into high gear. Skimping on sleep can blunt the release of hormones involved in muscle building and rejuvenation.

Yes, a few lucky “short sleepers” are genetically inclined to thrive on only about four hours of shut-eye per night, but this condition is extremely rare.5 “Most of the time when someone says they only need five or six hours of sleep, what that means is that their ability to tolerate sleep deprivation is better than most,” says Meeta Singh, a sleep specialist at the Henry Ford sleep laboratory. “They’re actually walking around with sleep debt, and have forgotten what it feels like to be awake and alert.”

The results showed that people who’d only spent six hours in bed were as impaired as those who’d consumed two to three beers, while four hours of rest was equivalent to about five or six beers. Staying up all night was like throwing back ten to eleven beers and then trying to function normally.

The people who’d slept an average of six or fewer hours per night during the previous week were far more likely to develop a cold than those who’d slept seven or more hours. Forty-five percent of the people who’d slept five or fewer hours got sick, while less than twenty percent of the volunteers who’d averaged seven or more hours of sleep came down with a cold.

She drinks a cup of coffee, then lies down for a 20- or 30-minute nap, which is approximately how long it takes the caffeine to fully kick in. “When you wake up, you’re ready to go, and you don’t have that grogginess.”

The system doesn’t work perfectly and it can’t cull every false positive finding, but a 2015 analysis showed that after the launch of ClinicalTrials.gov in 2000, the proportion of trials that found a positive benefit plummeted.9 Prior to 2000, for example, 57 percent of large randomized, controlled trials sponsored by the National Heart, Lung, and Blood Institute showed that the treatment worked. After 2000, that number dropped to 8 percent.

A New England Journal of Medicine study calculated that dietary supplements are responsible for 23,000 emergency room visits per year in the United States.

The idea that exercise creates extraordinary nutritional needs doesn’t make a lot of sense when you consider that the body was made to move (being sedentary is what throws our nutritional needs off-kilter). Yet we are told again and again that our bodies need special nutritional coddling when they’re active.

It turns out, the body’s ability to recover can be hindered by a multitude of factors—insufficient sleep, not enough rest between hard efforts, poor nutrition, a bothersome cold virus, or, commonly, psychological stress. To the body, Halson says, stress is stress, whether it comes from a hard workout, a competition, a romantic breakup or, if you’re a student-athlete, the anxiety of final exams.

The fact that a whole industry has popped up to help healthy people find ways to feel anxious about their bodies seems like a statement about the weird times we’re living in.

Normal reference ranges use a 95 percent confidence interval, and that means that five percent of normal, healthy people will fall outside of that range. Calling these values abnormal is essentially a false positive, and because some of the companies that market tests to athletes use an even narrower reference range, that means they’re going to generate even more false positives. (They’re also, of course, incentivizing people to come back for retesting. Ka-ching!)

the greatest risks lie at very low and very high training loads. “A training spike on a very low chronic load is a perfect storm for injury,” he says, but “if you have a high training load we know you’re protected—to a point. A super high load? Maybe not.” The key, he says, is consistency.

Too much focus on numbers can be counterproductive. “Very few people take into account the psychological ramifications of all this science-y data,” says Steve Magness, the running coach and coauthor of Peak Performance. “The more you measure, the more you create athletes who are fragile. I’ve seen it at the largest stage with world-class athletes. They become dependent. If the fancy HRV or omega wave tells them they aren’t ready, then they believe they are not ready.”

there seems to be a plateau effect where at some point the body hits its capacity to improve. At the elite level of human performance, there seems to be some kind of biological performance ceiling—when you’re near the top, there’s only so much room left for improvement.

After decades of observing athletes and their habits, Martin has concluded that most popular recovery modalities work by exploiting the placebo effect. But he doesn’t see that as a reason to dismiss them. On the contrary, he views it as an opportunity. This is real mojo, and instead of calling it the placebo effect he prefers the terms “anticipatory response” or “belief effects.” He uses these alternative names, because people tend to dismiss the word placebo as a synonym for ineffective, when, in fact, these effects are real, and in some cases can be as powerful as many drugs. The difference is that you’re gathering up your body’s own resources to create the benefit.

friend recently asked me what I thought of icing. I asked her what she would say if I told her it didn’t help. “I wouldn’t believe you,” she said. She knew that it worked for her. It was an honest answer that explains why we cling to unproven and even debunked modalities even in the face of evidence that they don’t work. We know what we believe and won’t be dissuaded.

Nieman recruited a group of racers and asked half of them to forgo ibuprofen during the event, something many would-be participants were loath to do. Afterward, he compared pain and inflammation in runners who took ibuprofen during the race with those who didn’t, and the results were startling. Ibuprofen failed to reduce muscle pain or soreness, and blood tests revealed that ibuprofen takers actually experienced greater levels of inflammation than those who eschewed the drug. “There is absolutely no reason for runners to be using ibuprofen,” Nieman said.

Since Nieman’s study came out in 2006, other research has shown that using ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs) prior to exercise may actually impede tissue repair and delay the healing of bone, ligament, muscle, and tendon injuries.

Too bad that reviews of the scientific literature on stretching have deemed stretching all but useless for recovery. A 2011 Cochrane review analyzed twelve studies of stretching—one of them a field study that involved more than 2,000 participants—and concluded that “the evidence from randomised studies suggests that muscle stretching, whether conducted before, after, or before and after exercise, does not produce clinically important reductions in delayed-onset muscle soreness in healthy adults.” A more recent review concluded that static stretching might reduce running economy (a measure of how efficiently you run), doesn’t reduce the duration or intensity of delayed-onset muscle soreness, and doesn’t make a dent in injury risk either.5 Sure, stretching may make it easier to touch your toes or show off other signs of flexibility, but that doesn’t seem to translate into fewer injuries or less soreness.

There’s a ritualization to some of these recovery modalities that shouldn’t be overlooked. In a recent editorial, Jonas Bloch Thorlund from the University of South Denmark deconstructed why arthroscopic surgery for meniscal tears remains popular, despite compelling evidence that these procedures are essentially placebos, no better than sham surgery.11 Thorlund notes that surgery represents a ritualistic activity that fosters expectations, much like the way shamans do. There’s the journey to a healing place (the hospital), anointment with a purifying liquid (the presurgical skin prep), and an encounter with the masked healer. As I read this description, I felt a glimmer of recognition, thinking about my experiences visiting recovery centers. In each case, you’re greeted by an empathetic caregiver who walks you through a series of rituals that require various forms of preparation and waiting. It makes me wonder how much power resides in the simple act of putting your trust in a healer and taking part in the ritual on offer.

a small study of triathletes in their fifties showing that rates of muscle protein synthesis in these masters athletes were lower than those of athletes in their twenties.1 His research suggests that older athletes may have an “anabolic resistance” to protein that makes it harder for their bodies to convert protein into muscle, and that may help explain why it takes longer for them to repair exercise-induced muscle damage. (It’s also an argument for keeping your protein intake up as you age.)