Numlock Sunday: February 3, 2019

By Walt Hickey

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Welcome to the Numlock Sunday edition. Each week, I'll sit down with a writer behind one of the stories covered in a previous weekday edition for a casual conversation about the story they wrote.

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This week, I spoke to Christie Aschwanden, who’s got a great new book coming out this week about the science behind recovery from workouts.

The book, Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery, busts recovery myths, dives into the actual science and is full of cool stories in a field too often hit with pseudoscience products. Christie’s responsible for some of my favorite stories out there, and getting to work with her on some projects back at FiveThirtyEight was a major highlight, and I’m thrilled to see this book hit shelves.

We talk about everything from obeying thirst to Tom Brady to sensory deprivation chambers.

Christie can be found on Twitter, Good to Go hits shelves on Feb. 5, and you can find a copy here.

This interview has been condensed and edited.

Walt Hickey: What got you interested in looking at the science of recovery?

Christie Aschwanden: It started with beer actually!

It's a fairly common thing that runners — weekend warrior types — like to get together and have a beer after our activities. Several of the running groups that I'm in will go for a run and then finish up at the local microbrewery. This is all fine and great, but I started wondering: could it be possible that this beer — specifically the alcohol in the beer — might be impairing our recovery?

That seems like a really easy question, but it turns out that it was really difficult to answer. In fact, I talked Runner's World (I used to be a contributing editor there) into funding a study. We got together with researchers at Colorado Mesa University and did a study to look at this. It was much, much harder than I expected. That's what first sent me down this rabbit hole of looking at the research on recovery and just looking at the larger question: how do we really know what works and what doesn't?

I had heard you talk a little while ago in New York for a podcast. It was about how even hydration is not cut and dry science.

It's really interesting. People were studying hydration and looking at football players who were wilting in the heat and were having trouble. I think anyone who's ever tried exercising in the heat knows that it's really hard, and you feel terrible and it's easy to not feel good. Players were collapsing and developing health problems and heat stroke as a result of the heat.

The question was how do we prevent this, and how do we help our players to be able to handle the heat better? Really soon the research started honing in on hydration. The idea was "Okay, we need to keep them hydrated," as hydration seems to be really related to heat stroke.

On the one hand, it is absolutely true that when you're exercising in the heat, you sweat more and you're going to need more fluids and all of that. But it turns out that hydration and heat stroke are not the same thing. There was a really large study done by the military actually over many years. They found that only something like 20 percent of cases of heat stroke had dehydration involved. It wasn't a matter of people just not drinking enough water. Guess what, it turns out that when you exert yourself hard in the heat, that's what seems to be related to heatstroke. How much water you drink is not the most critical thing.

Again, I want to just be really clear I'm not at all saying, "you shouldn't drink in the heat," or, "it's not important to drink more when its hot." But that isn't the be all, end all of heat stroke.

As researchers kept going on and looking at hydration, then you had drink companies coming in and making products. And all of a sudden, when you have products that are being sold, then you get marketing involved. Then it becomes this thing where "dehydration is now scary and you have to prevent it" and "you have to drink before you're thirsty" and "you have to drink early and often." And it turns out that when you look at the research, a lot of that stuff is unsupported.

Nobody's making money off of taking a break and spend a few minutes in the shade. It's all about quenching thirst.

Right. But actually, quenching thirst is great. That's what you should be doing. It turns out that the very best evidence-based advice for hydration is to just drink when you're thirsty.

It is true that it's probably a good idea to pay attention: it's possible if you're not thinking about hydration that maybe you don't notice those thirst signals. It's a good idea to think about it, but if you're not thirsty, you don't need to drink. You basically don't need a scientist or researcher looking over your shoulder telling you how much you need to drink on some sort of schedule.

Our bodies are really sophisticated! They have this extremely sophisticated mechanism to get you to drink enough. It's called thirst. There used to be a slogan, "Obey your thirst," and that's actually probably the perfect slogan for hydration. Obey your thirst and you'll be fine.


That's really good news. So anybody who is involved in fitness — not me, but I'm told by other people who are — gets a lot of information about products and services, and part of the book is about seeing what's effective. What are some things that you expected would be effective and weren't?

I always thought that icing was great. When I was a serious athlete we would often do ice baths, the idea being that it would reduce soreness. It turns out that ice doesn't reduce soreness. There's not good evidence for that. The evidence is mostly in studies where they're asking people, so they have expectation effects, and we can't be sure that it's not a placebo.

What's really interesting about icing is that there's also this idea that it works by reducing inflammation, but it turns out that inflammation is a really important thing. If you are training, or you're exercising in order to get faster, stronger, better, you want inflammation. Inflammation is your body's repair mechanism and process. That doesn't mean that you want your body to be swollen or anything like that. But the inflammatory molecules and the inflammatory process is essential for adaptation. If you're training really hard with the idea that you're going to increase your endurance and your power and your strength and all of that, you want that inflammation process to go on. Because if you impair it, you could make fewer gains. This has been shown in studies which I describe in the book! There's a whole chapter about cold therapy and icing and ice baths in the book.

This is an interview that is coming out on Super Bowl Sunday and you wrote a book about athletic recovery. It would be illegal for me to not use the words "Tom Brady" in this interview. I know you looked at some of the stuff that he's involved in and other athlete trends. What's Mr. Brady's deal?

Mr. Brady does make an appearance in the book -- several appearances I believe -- but one big section in which he appears is a whole chapter on sleep. Sleep, it turns out, is the most potent recovery tool you can do. Everything else is just icing on the cake. Tom Brady is currently endorsing some pajamas that claim to use infrared radiation to work their magic.

It's really interesting because what's happening here is you have something that is legit -- the most important recovery thing you can do, which is sleep -- that is being turned into a commercial product, right? It's being commercialized. You can't actually sell sleep, but you can sell these things that claim to help people sleep better. But it was interesting when I was looking into Tom's magic pajamas, what I found is that he also was giving some really good advice about sleep and sleep hygiene. Things like going to bed early, having it dark in your room, cutting down on noise, turning all of your screens off before bedtime. So all of that is good! The pajamas themselves, they didn't find any magic there and some of the claims really didn't hold up. But the idea of sleep did! It was kind of the commodification of something that isn't easily commodified.

You did guinea pig some stuff -- cryo chambers, float tanks, infrared saunas. Regardless of what is actually beneficial to you for recovery, which was the most fun?

Oh, good question. I talk in the book about how I tried some float tanks, which I actually really expected to hate. I'm a little bit claustrophobic. It's dark. You're basically floating in a few inches of saltwater in an enclosed chamber. And that sounds to me like torture. In fact, they used to be called sensory deprivation chambers, which sounds kind of like torture, right?

It turns out that I love that.

It's basically forced meditation and so it's the perfect thing for me. It's something that I'm continuing to do to this day, not every day, but it's one of the things that I tried that was new to me that I really discovered was helpful for me. That's not to say that everyone will find it useful, but I think one important takeaway from the book is that we tend to think of recovery as being like, "I trained really hard today, so now I need to recover." Thinking of it just in terms of the exercise. But emotional and other kinds of stress are just as hard on your body and to your body.

Whether you're an elite or a weekend warrior, one of the most important things that you could do to aid recovery is to reduce the stress in your life. You have to figure out some kind of way of coping with stress and that's going to be really individual for you. For me, float tanks are great. They really helped me relax into the right mindset. Other people will find massage, some people like to just meditate on their own. Whatever it is, find the thing that works for you. That will help a lot.

The book is out Feb. 5 and is called Good To Go. Any other plugs? You're launching a podcast soon, right?

You can go here and there are links to order it from any of the major retailers as well as inbound, which will allow you to order it from your local independent bookstore. In the middle of February I'm launching a new podcast, it's called Emerging Form. It's a podcast about the creative process and it is sort of a side project, a labor of love between me and one of my best friends who's a poet. It's the two of us talking about the creative process and then each episode we bring on a guest to help us talk about whatever the topic is and answer a couple of questions. Season one has episodes on topics ranging from a talent to collaboration to existential despair.


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