Recovery has become a verb, says science journalist Christie Aschwanden. For optimal athletic performance, it’s no longer enough to stop exercising and take a couple days of rest. Now we need to drink Gatorade, spend time in saunas, and float in tanks. But does any of that really work?
It’s complicated, says Aschwanden, a science writer for FiveThirtyEight and author of Good to Go: What the Athlete in All of Us Can Learn From the Strange Science of Recovery. An athlete herself, Aschwanden found that as she grew older the need for recovery became more and more noticeable. And while there have been a few technical and how-to books on the topic, Aschwanden wanted to learn the science behind these ultra-hyped methods, try them out for herself, and figure out what it even means to “recover.”
The Verge spoke to Aschwanden about problems in sports science, why dehydration isn’t a huge risk, and what the best recovery advice might actually be.
This interview has been lightly edited for clarity.
What exactly is “recovery”?
There’s no doubt that recovery is absolutely crucial. It’s important, that’s very clear, but how
do you measure it? That’s actually a really difficult question. [In one study] we used “run to exhaustion,” which as a participant I found was not a good measure and seemed to measure how much boredom we could endure.
A lot of times it’s easy to study the things that you can measure rather than the things that actually matter. Then you have situations where people studying hydration and heatstroke chase the wrong outcomes and the wrong measures because they weren’t stopping to make sure they were studying the right thing.
What happened in the case of hydration and heatstroke?
You hear all the time that “by the time you’re thirsty, it’s too late, you need to drink before then.” But I looked long and hard and was not able to find a single instance in an athletic instance or a marathon of someone dying of dehydration. What I did find is numerous people who died from drinking too much water. It’s a medical condition where your blood becomes too diluted and you get brain swelling. It’s a terrible, terrible thing.
You need to drink often, but you can drink too much and that’s much more dangerous than not drinking enough. Of course if you’re in the desert and you run out of water it is possible to die of dehydration, but it’s not something people are dying of on the athletic field.
In fact, when you’re exercising, your body is well-adapted to not being plied with water at every moment. It’s called adaptive hydration and that may even be performance-enhancing. Our ancestors did not walk around with water bottles. In one marathon, the winner lost something like 10 percent of his body weight through sweat during the event. If you’re not losing some water weight that should be expected. It’s adaptive.
The thing is, dehydration is conflated with heatstroke, which really is dangerous. But it turns out that heatstroke is almost never related. The two are not one and the same, it’s just that dehydration became this catch-all phrase. If something happens, people cite “dehydration.”
Clearly, dehydration isn’t the best way to measure recovery. Is there one?
I was surprised by the the extent to which there are so many efforts to quantify recovery. All these companies trying to find “the magic metric,” that thing you can measure on a watch or blood test and so you’ll know whether you’ve optimized your recovery. But the very best thing we have is this subjective measure of “how do we feel?”
The subjective measures trump the objective measures every time in multiple studies and analyses. It turns out our brains are the most sophisticated instruments here in ascertaining recovery and that psychological feeling of wellness and readiness is the very best measure of recovery,
I don’t think that’s intuitive, but for me it was really heartening. We’ve really turned this thing into something that’s far more complicated and more daunting than it needs to be, and it’s okay to trust how you’re feeling. Really, the most important skill and most important thing that an athlete can develop is what their body is telling them and a sense of “how do I feel when I’m not recovered and when I am?”
One theme I noticed throughout the book is that almost everything you write about, from Gatorade to saunas to fancy pajamas to cryotherapy, seem overhyped. How can we as consumers see through that?
Any time you have a product that’s for sale or something that’s being pushed by producers of a particular food crop or something like that, that’s a reason to be skeptical. One interesting story I talk about is chocolate milk and what happened there. Researchers did some studies looking at chocolate milk as a possible recovery aid and the milk producer said, this is marketable. This didn’t mean that it wasn’t a good idea, but what can happen is that marketing takes over and the tendency to overstate whatever findings there actually are. You want to ask, where did they get their funding for these studies? Very often it comes from companies producing these drinks or supplements or aids.
And some of the studies, too, don’t seem to be super strong.
Right. It’s a problem that pervades most of sports science. You’re looking for small effects, using small sample sizes.
Our ancestors did not walk around with water bottles.
It’s hard to get reliable answers. It’s hard to have a representative sample and know that the finding you’re getting in a small group will generalize to other athletes. Very many sports science studies are on the order of 10 to 12 per group, and you’d never see that, for the most part, in a clinical trial. It’s hard to get reliable answers. And if you’re studying elite athletes, there just aren’t a lot of them to recruit enough people to get a large sample.
The fascinating thing, though, is that at the same time, you said that some of the things that you investigate in the book — including things as simple as ice baths — do “work” in that they make you feel better, even if you’re not actually recovering faster. What does that mean?
In a lot of cases, there are things that really truly do work in the sense that they make you feel better. Recovery is a feeling, it’s a sense that your brain takes all of the inputs and turns that into a feeling of being tired or not being tired or feeling sore, so anything that makes you feel better, is “working.”
But we’re so eager to look at something that’s a physiological and when you look at those kinds of things, there aren’t quantitative measures that can prove that it’s helping. Many of these things are actually rituals where the athlete is taking some time to rest or put their feet up or not to do something that’s not “recovery.” A good example is icing or those compression boots that sort of massage your legs. It feels good. It’s relaxing. You’re not running around. I mean, at a basic level, recovery is just... rest, so anything that helps you do that is great and effective. So you can say, “Well, there’s no good scientific study showing that some of those things work,” but if they make people feel better and take time out, that’s going back to the things that matter. One conclusion of the book is that one of the most potent things you can do for recovery is sleep.