Book Review: Good to Go, by Christine Aschwanden

This is a book review. It is by Phil Price. It is not by Andrew.

The book is Good To Go: What the athlete in all of us can learn from the strange science of recovery. By Christine Aschwanden, published by W.W. Norton and Company. The publisher offered a copy to Andrew to review, and Andrew offered it to me as this blog’s unofficial sports correspondent.

tldr: This book argues persuasively that when it comes to optimizing the recovery portion of the exercise-recover-exercise cycle, nobody knows nuthin’ and most people who claim to know sumthin’ are wrong. It’s easy to read and has some nice anecdotes. Worth reading if you have a special interest in the subject, otherwise not. Full review follows.

The book is about ‘recovery’. In the context of the book, recovery is what you do between bouts of exercise; or, if you prefer, exercise is what you do between periods of recovery. The book has great blurbs. “A tour de force of great science journalism”, writes Nate Silver (!). “…a definitive tour through a bewildering jungle of scientific and pseudoscientific claims…”, writes David Epstein. “…Aschwanden makes the mid-boggling world of sports recovery a hilarious adventure”, says Olympic gold medal skier Jessie Diggins. With blurbs like these I was expecting a lot…although once I realized Aschwanden works at FiveThirtyEight, I downweighted the Silver blurb appropriately. Even so, I expected too much: the book is fine but ultimately rather unsatisfying. It is fairly interesting and sometimes amusing, but there’s only so much any author can do with the subject given the current state of knowledge, which is this: other than getting enough sleep and eating enough calories, nobody knows for sure what helps athletes recover between events or training sessions better than just living a normal life. The book is mostly just 300 pages of elucidating and amplifying that disappointing state of knowledge.

The author, Aschwanden, went to a lot of trouble, conducting hundreds of interviews, reading hundreds of scientific or quasi-scientific or pseudo-scientific papers, and in some cases subjecting herself to treatments in the interest of journalism (a sensory deprivation tank! Tom Brady’s magic pajamas! A cryogenic chamber!…) If the subject of athletic recovery is especially interesting to you then hey, it’s a fine book, plenty of good stuff in there, $30 well spent for a two or three hours of information and amusement.

For readers of this blog — and maybe for everybody — the first couple of chapters are the best ones, because they provide some insights that can apply to many areas of science and statistical analysis. The first chapter explains what happened when Aschwanden became interested in whether beer is good, bad, or indifferent as a ‘recovery drink.’ She has a friend who was a researcher at a lab that researches human performance and when she brought the question to him he was enthusiastic about studying this issue, so they did. They designed and performed a study that is typical (all too typical) of studies that address this kind of issue: only 10 participants, with tests spanning a couple of days. Do some hard exercise, then drink regular beer or non-alcoholic beer. The next day “run to exhaustion” (following a standard protocol) and afterwards drink whichever beverage you didn’t drink the previous day. The next day, run to exhaustion again. Quantify the time to run to exhaustion at the specified level of effort. The study found no ‘statistically significant’ difference between real beer and fake beer for the contestants as a whole, or for male participants, but for women there was a statistically significant difference, with performance better after real beer! And for men there was a difference large enough to be substantively important if true, but not statistically significant. Fortunately, Aschwanden is no dummy. She doesn’t mention the ‘garden of forking paths’, but does recognize some other major methodological problems with the study. As she puts it: “There was only one problem: I didn’t believe it. Trust me — I wanted our study to show that beer was great for runners, really, I did. Yet my experience as a participant… left me feeling skeptical of our result, and the episode helped me understand and recognize some pitfalls that I’ve found to be common among sports performance studies.” And then she gives a few paragraphs that do a great job of illustrating why it is really hard to get objective measures of human performance for a study like this, and why it matters. The upshot is that in this study the researchers are fitting noise. And the problems that came up in this study are common, indeed nearly ubiquitous, in this sort of research. Disappointingly, even this chapter doesn’t show any data or any hard numbers. There’s not a plot or table in the book.

The second chapter discusses hydration (and over-hydration), starting off with a discussion of the creation and marketing of Gatorade and going on from there. As with every chapter, Aschwanden mixes anecdotes, history, and results from scientific studies, and pulls everything together with her own evaluation. It’s a good formula and makes for a readable book. The hydration chapter is typical in that it illustrates the extent to which marketing and a smattering of scientific research led to a widespread perception among athletes that later turned out either not to be true or to be more nuanced than was first thought. In fact, according to Aschwanden and backed up by many studies she cites, in contrast to what many athletes and coaches have believed over the past thirty years or so our bodies can tolerate moderate dehydration with very little problem, and optimal hydration for a many athletes and many activities turns out to involve a lot less drinking than most people (including most athletes and coaches) thought for decades. And it’s probably better to be rather dehydrated than to be rather over-hydrated.

I can’t resist adding my own little hydration story. A couple of years ago, on a very hot day I rode my bike on a hilly route to our local mountain (Mount Diablo), rode up it and back down, stopped at the bottom for food, and then rode back home. The ride was about 100 miles and the temperature was in the high nineties. Each time I stopped for water, I filled and chugged one of my water bottles, then filled both of them and continued on, draining both bottles by the time I got to the next water stop. Knowing the capacity of my bottles and the number of times I stopped, it’s easy to count how much I drunk that day. I also had a large milkshake and a coke at my lunch stop, as well as something like a pound of food. On that day I drank 17 pounds of fluid. I weighed myself when I got home and found that I had lost 8 pounds. I had not urinated during the day, and didn’t do so for several hours after I got home. What’s the point of telling you this? I dunno; I just think it’s really interesting. In one long day I sweated or exhaled more than 25 pounds of water! I still find it hard to believe..although it does jibe with one of Gatorade’s early marketing campaigns, which promoted the idea that athletes should drink 40 ounces per hour, and not necessarily on a brutally hot day. But Aschwanden has both anecdotes and studies in which successful athletes drank much less, and about some athletes getting in bad medical trouble by drinking too much.  The point isn’t that endurance athletes shouldn’t drink, it’s that they shouldn’t obsess about drinking as long as they don’t get too thirsty. Aschwanden says it has long been conventional wisdom that in an athletic event you should drink before you’re thirsty, and drink enough that you never become thirsty, but there’s actually no evidence that that leads to better performance than simply drinking when you feel like it.

Another chapter covers the current fad for ice baths, cryogenic chambers, ice-water compression boots, and so on. No real evidence they help, no real evidence they hurt.

Another chapter covers the current fad for infrared treatments (heat baths, saunas, ‘infrared’ saunas, Tom Brady’s magic thermal underwear, etc.) No real evidence they help, no real evidence they hurt. Oh, and not only have the claims about thermal underwear not been evaluated by the Food and Drug Administration, they’ve apparently never been evaluated by a physicist either, because they’re ridiculous. If you buy the underwear you deserve to be mocked, and you should be. If no one else will do it for you, send me an email and I’ll do the mocking.

Massage? No real evidence it helps, no real evidence it hurts. That said, I intend to continue to get occasional massages from my next door neighbor, Cyrus Poitier, who is an elite sports masseur. He travels with the men’s national wrestling team and the women’s swim team, and is one of the US Olympic Team’s masseurs. Like most of Cyrus’s clients, I don’t go to Cyrus for feel-good massages — in fact they are usually quite painful — but instead I go when I have some soreness or tightness that I haven’t been able to get rid of on my own, and I do think his massages help. But do they really, in the sense of helping me perform better athletically, and, if so, how much? According to Aschwanden there’s no evidence, or only weak evidence, that they help at all. But I would swear they help me! And he has many elite athletes as clients. So are all of us wrong? Well, maybe we are, or maybe we’re right that the massages help but the effect is rather small. Or maybe they help the performance of those of us with some musculo-skeletal issues but harm the performance of people with other issues. The right way to answer this is with data, and according to Aschwanden the existing data aren’t adequate to the task.

Every ‘recovery modality’ in the book has a bunch of proponents, including some elite athletes who swear by it. Every one of the modalities has a bunch of individuals or companies promoting it and telling people it works, usually buttressed by questionable studies like Aschwanden’s beer study.  And just about every one of the recovery methods or substances has some skeptics who think it’s all hype.

And ultimately that’s the problem with Aschwanden’s book, though it’s not her fault: at the moment it’s impossible to know what works, and how well. She says this herself, towards the end of the book: “After exploring a seemingly endless array of recovery aids, I’ve come to think of them as existing on a sort of evidence continuum. At one end you’ve got sleep — the most potent recovery tool ever recovered (and one that money can’t buy). At the other end lies a pile of faddish products like hydrogen water and oxygen inhalers, which an ounce of common sense can tell you are mostly useless… Most things, however, lie somewhere in the vast middle — promising but unproven.” For someone like me, that’s a good reason to ignore just about all of the unproven stuff: even if something would improve my performance fairly substantially — let’s say a 5% increase in speed on my hardest bike rides — that wouldn’t change my life in a noticeable way. But for a competitive athlete, even 0.5% could be the difference between a gold medal and being off the podium, or being a pro vs an amateur who never quite breaks through. So there are always going to be people promoting this stuff, and there will always be athletes willing to give it a try.

Although firm conclusions about effectiveness are hard to come by, there’s plenty of interesting stuff in the book. For example, one of the many anecdotes concerns sprinter Usain Bolt. At the 2008 Olympics in Beijing, Bolt wasn’t happy with any of the unfamiliar food available to him at the athletes’ cafeteria, so he went to McDonalds and ate Chicken McNuggets. Every day. For lunch and dinner. (He also ate a small amount of greens drenched in salad dressing). According to Bolt’s memoir, he ate about 100 nuggets every 24 hours, adding up to about 1000 chicken nuggets over the course of the ten days he competed in the 100m, 200m, and 4x100m relay (with multiple heats in each, plus the finals). He won gold medals in all of them. As Aschwanden says, “Those chicken nuggets were adequate, if not ideal, fuel to power him through his nine heats, and to help him recover his energy in between them. Feeling satiated and not worrying about gastrointestinal issues are surely worth a lot to an athlete preparing for his most important events of the season. Would Bolt have performed better eating some other recovery foods? Maybe. The better question is: How much difference would it make?”

By the way, a popular saying among the kind of people who read this blog is “The plural of ‘anecdote’ is not ‘data.’” I liked that saying too, the first time I heard it, but the more I think about it the less I agree with it. Of course it’s literally true that ‘data’ is not the plural of ‘anecdote’, since the plural of ‘anecdote’ is ‘anecdotes.’ But each (true) anecdote does provide a data point of sorts. A sprinter won three gold medals on a diet consisting almost entirely of Chicken McNuggets, and his 100m time was a world record even though he didn’t run all the way through the tape. That really does set an upper limit on how deleterious a week of Chicken McNugget consumption is, at least to Usain Bolt. As far as data go, that anecdote is probably more informative than the quantitative results of Aschwanden’s 10-participant beer study, no matter how carefully the study was conducted.

One of the good things about Aschwanden’s book is that she puts the pieces together for us. She’s smart, she’s a former elite athlete herself (a professional cross-country skier), she talked to hundreds of people, she read lots of scientific studies, and she formed well-informed beliefs about everything she writes about. Only a tiny portion of those interviews and studies can fit in the book, but I trust her judgment well enough to think I’d probably reach most of the same conclusions she did, so I appreciate the fact that she does summarize her beliefs. A few key ones are: (1) ‘recovery’ involves both mind and body, and stress of all kinds — physical, mental, and emotional — hurts recovery of both mind and body. (2) Sleep is especially important to recovery; relaxation is too. If an athlete’s recovery routine is itself a source of stress, it’s counterproductive. (3) Under-eating is bad, and is worse than eating non-optimally. (4) The timing of food intake is unimportant unless you have a short break between events. If you finish an event and you have another one in a few hours, eating the right thing at the right time is critical. But if you aren’t competing again for 24 hours or more, there is no ‘nutrition window’, there’s a nutrition ‘barn door’, in the words of one researcher she quotes. (5) Other than getting enough sleep and enough relaxation, and eating enough to replenish glycogen supplies and calories in time for your next event, nearly nothing else is definitively known to be beneficial compared to just living an ordinary life between events. (6) Overtraining is real thing, with both physical and mental components, and overtraining can be worse than undertraining. (7) With regard to specific ‘recovery modalities’: Massage might or might not help; ice baths might or might not help (and in fact might harm recovery a little); various food supplements might or might not help; heat in various forms might or might not help; ibuprofen and other anti-inflammatories probably do a little physical harm in most people, but most athletes refuse to believe it; stretching probably doesn’t help most people. (8) Different things work differently for different people, so following the same recovery routine as your sports idol might not work for you; (9) Some recovery methods, maybe a lot of them, really do help some people simply due to the ‘placebo effect’, and there’s nothing wrong with that: if it helps, it helps.

If any of these points seem odd or wrong or questionable to you, then I suggest reading the book, because Ashwanden explains why she has adopted her viewpoint. If you agree with all of them but want support for them, that’s another reason to read the book. If you agree with them all, shrug, and say “yeah, that’s pretty much what I figured” then you can skip the book unless you are interested in some interesting stories like the one about Bolt.


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