Epistemic Spot Check: Exercise for Mood and Anxiety (Michael W. Otto, Jasper A.J. Smits)


Everyone knows exercise (along with diet and sleep) makes a big difference in depression and anxiety.  Depressed and anxious people are almost by definition bad at transforming information about how to improve their lives into actions with large up front costs, so this data is not as useful as it might be.  Exercise for Mood and Anxiety (Michael W. Otto, Jasper A.J. Smits) aims to close that gap by making the conventional wisdom actionable.  It does that through the following steps:

  1. Present evidence that exercise is very helpful and why, to create motivation.
  2. Walk you through setting up an environment where exercise requires relatively little will power to start.
  3. Scripts and advice to make exercise as unmiserable as possible while you are doing it.
  4. Scripts and advice to milk as much mood benefit as possible from a given amount of exercise.
  5. An idiotic chapter on weight and food.


Parts 3 and 4 use a lot of techniques from cognitive behavioral therapy and mindfulness, and I suspect there’s a second order benefit of learning to apply these techniques to a relatively easy thing, so you can apply them to the rest of your life later.

Epistemic Spot Checking

Claim: “a study of 55,000 adults in the United States and Canada found that people who exercised had fewer symptoms of anxiety and depression.” (Kindle Locations 103-104). 

Correctly cited, paper has no proof of causation.  (abstract) (PDF) The study does in fact say this, but it also says “Despite the fact that none of these surveys [of which this paper is a metaanalysis] was [sic] originally designed to explore this association… “.  I’m not saying you can never repurpose data, but with something like this where the real question is causality, it seems suspicious.  The authors do consider the idea that causation runs from mental health (=energy, hopefulness, executive function) -> exercise and dismiss if, for reasons I find inadequate.

Claim: “Other studies add to this list of mood benefits by indicating that exercise is also linked to less anger and cynical distrust, as well as to stronger feelings of social integration.” (Kindle Locations 104-106). 

Correctly cited, paper has no proof of causation. (Abstract).

Claim: And these benefits don’t just include reducing symptoms of distress in people who have not been formally diagnosed with depression or anxiety. The benefits of exercise also include lower rates of psychiatric disorders; there is less major depression, as well as fewer anxiety disorders in those who exercise regularly. (Kindle Locations 107-109). 

Correctly cited, paper has no proof of causation.

The dismissal of causality goes on for another three citations but I’m just going to skip to the intervention studies.  Otto gives these population studies more credence than I would but does note that the intervention studies are more informative.

Claim:  study summarized 70 studies on this topic and showed that adults who experience sad or depressed moods, but not at levels that meet criteria for a psychiatric disorder, reliably report meaningful improvements in their mood as they start exercising. (Kindle Locations 116-117).

Correctly cited, study accuracy undetermined.  (Full paper). My fear (based on spot checking a similar book you’ll see in the rejects post) is that each of these studies consists of 15 people.  All the metaanalysis in the world won’t save you if you do 100 small studies and only publish the 50 that say what you want.  The studies included go all the way back to 1969: I can’t decide if that makes them more informative or less.

Claim:  The latest estimates are that about 17% of adults experience a major depressive episode in their lifetimes and that about half who have it experience recurrent episodes over time. (Kindle Locations 124-126). 

True. (Full paper).  The same study is cited for both facts, but I can only find the 50% statistic in the paper.  The data is kind of old (started in 1981), but of course you can’t get 30-year data except by starting 30 years ago.  This paper says the lifetime prevalence of mood disorders (depression, bipolar 1 and 2, and their baby siblings) is 20%; this study puts prevalence in the US at 16.9%.

Claim: As is the case with major depressive disorder, anxiety disorders are common, affecting more than 1 in 4 (28.8%) adults in their lifetimes” (Kindle Locations 136-137).

True. (Full paper).  He cites the same paper I did for the 20% mood disorder statistic.

Claim: [Anxiety disorders] tend to be especially long-lasting when people do not receive treatment. (Kindle Locations 137-138).

True, although not particularly specific.  (Full paper)

Claim: Exercise in itself is a stressor—it requires effort, and it forces the body to adapt to the demands placed on it.  (Kindle Locations 141-142). 

True.  (Full paper).

Claim:  A study examined firefighters reaction to stress, and then gave half a 16 week exercise course.  The study group showed improvements in stress responses. (Kindle location 148)

True.  (Abstract) (PDF).  I really like this study.  The group presumably had a high baseline fitness level, so this isn’t the difference between couch potato and a walk.  And they have before and after metrics.  The study is marred only by the small sample size (53).

Claim: “stress plays a key role in both the development and the continuation of depression and anxiety disorders.” (Kindle Locations 152-153). 

Accurate citation, very complicated topic. (Abstract).

Okay, it is becoming clear I don’t have the time to check every one of these citations and you don’t have time to read it.  From here on out please assume a baseline of very dense citations, all of which accurately report the study results, if with a little more confidence than the study design merits, and I’m only going to call out things that deserve special attention on account of controversy or importance.

Claim: exercise increases serotonin just like the primary class of anti-depressants, selective serotonin update inhibitors.

True but less relevant than implied.  They’re relying on a model of how SSRIs treat depression that is fairly outdated.  SSRIs definitely increase serotonin, it’s just that there’s no evidence that’s their mechanism of action against depression except that they do it and they treat depression.  “Depression is caused by a serotonin deficiency” is a lie simplification told to patients and their families to allay fear and shame around psychiatric treatment.  This doesn’t undercut their point that exercise is good for you, but does indicate this is not a great book to learn brain chemistry from.

Claim:  Both aerobic (prolonged moderate exercise such as running, cycling, or rowing over time) and anaerobic (like weight lifting or short sprinting) exercise have been found to be effective for decreasing depression, (Kindle Locations 239-241).

True. (Study 1 PDF) (Study 2 abstract).


Empirical Results

The theory behind this book is very well supported; the prescriptions it makes flow naturally from the theory, but the authors present no direct evidence that they work.  I’m torn about this.  I don’t want to engage in RCT worship; having a systemic understanding of a problem is even better than evidence a particular solution worked better or worse than another solution in a different population.  On the other hand, humans are very complicated and it’s easy to identify the problem but guess the wrong solution.

I couldn’t test any of this on myself because I already enjoy exercise for a lot of reasons, so I scrounged up an unscientific sample from my wider social network to try it.

14 people filled out the pre-book survey.  3 people filled out the post-attempt survey.  None of them exercised more.


The theory sections of this book are my high water mark for scientific rigor in a self-help-psych book.  I’m currently reading a lot of those with the goal of finding out how much rigor is reasonable to expect, so that’s high praise.

The book walks the very fine line between reassuring and condescending, which is pretty unavoidable with CBT and mindfulness.

I did not like the last chapter and recommend skipping it.  It feels like they tried to stuff all the usual diet-and-exercise stuff in at the end.  Some of my problem is I think their recommendations are wrong, and some is that I believe that even if they were correct, throwing them in at the last minute undercuts the message of the book.

The first part of this is that, in America, at least in certain subcultures, any mention of weight makes the whole thing About Weight.  Too many people use health or mood as a socially acceptable way to say “you’re not hot enough”, so any mention of weight in the context of diet or exercise automatically makes weight the real topic of the conversation.  If the improvements in mood are enough of a reason to exercise, let them be enough, and the weight loss can be a pleasant surprise or not happen, and both are okay because you got what you came for.

The authors compound this problem by using Body Mass Index as a guide for goal weight.  BMI is completely unsuited for use in individuals, even more so for people who just started gaining muscle mass.  If you must talk about fat in the context of health use body fat percentage or certain circumference ratios (e.g. wrist:stomach).

The second problem is the speed with which EFMaA tries to address nutrition.  The book (correctly) treats exercise as a thing that is challenging to start despite all its benefits, and spends 10 chapters explaining why it’s worth trying and providing scripts to make it workable for you, for the sole benefit of mood, ignoring everything else you might get out of exercise.  I don’t know why the authors thought that that required an entire book but the even more complicated of nutrition for every possible benefit of nutrition could be squeezed into half a chapter.  I would be have been very excited for another book by the same authors about how to implement healthy eating, but the half assed treatment here makes me pause.

They also present a particular diet as the settled science, when there is no such thing in nutrition.  “Eat produce and fish” is fairly uncontroversial, but they recommend a lot more refined grains than many other people.  I don’t know who is correct, but it was disappointing to see a book that had been so rigorous up to that point blithely paint over controversy.

[I have emailed Michael Otto about the handling of nutrition and have yet to hear back].

Speaking of which Exercise for Mood and Anxiety mentions that both aerobic (cardio) and anaeorbic (weights) are good for mood, but every single example is cardio, with an occasional cardio + core strength.

Mixed in through the book are tales of how Olympic athletes motivate themselves.  This feels spectacularly irrelevant to me.  I don’t want to win a gold medal, I want to climb V2s and be happy.

You might find this book valuable if:

  • You want some ideas (although not conclusive proof) around how exercise helps mood.
  • You want to want to exercise, and want scripts and tools to transform that into “want to exercise right now.”
  • You find exercise unpleasant and want to get the best trade of unpleasantness-for-benefits possible.
  • You would like to treat a mood issue with exercise (whether it reaches the level of official disorder or not).
  • You want to change how you think about exercise (for improving your mood or something else).
  • You are interested in CBT or mindfulness and want to practice with the large print version before tackling them directly.
  • You think you are different than my test audience.

You probably won’t find this book valuable if:

  • You already have an exercise program you are happy with.
  • You have body image or eating disorder issues (last chapter only, and a single section of the 10th,  the rest of it is fine).
  • You want prescriptions for a particular exercise program, as opposed to general principles.
  • You want to learn the nitty gritty of how exercise affects mood.
  • You are similar to my test audience.



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Epistemic Spot Check: A Guide To Better Movement (Todd Hargrove)

Edit 7/20/17: See comments from the author about this review.  In particular, he believes I overstated his claims, sometimes by a lot.


This is part of an ongoing series assessing where the epistemic bar should be for self-help books.


Thesis: increasing your physical capabilities is more often a matter of teaching your neurological system than it is anything to do with your body directly.  This includes things that really really look like they’re about physical constraints, like strength and flexibility.  You can treat injuries and pain and improve performance by working on the nervous system alone.  More surprising, treating these physical issues will have spillover effects, improving your mental and emotional health. A Guide To Better Movement provides both specific exercises for treating those issues and general principles that can be applied to any movement art or therapy.

The first chapter of this book failed spot checking pretty hard.  If I hadn’t had a very strong recommendation from a friend (“I didn’t take pain medication after two shoulder surgeries” strong), I would have tossed it aside.  But I’m glad I kept going, because it turned out to be quite valuable (this is what triggered that meta post on epistemic spot checking).  In accordance with the previous announcement on epistemic spot checking, I’m presenting the checks of chapter one (which failed, badly), and chapter six (which contains the best explanation of pain psychology I’ve ever seen), and a review of model quality.  I’m very eager for feedback on how this works for people.

Chapter 1: Intro (of the book)

Claim: “Although we might imagine we are lengthening muscle by stretching, it is more likely that increased range of motion is caused by changes in the nervous system’s tolerance to stretch, rather than actual length changes in muscles. ” (p. 5). 

Overstated, weak.  (PDF).  The paper’s claims to apply this up to 8 weeks, no further.  Additionally, the paper draws most (all?) of its data from two studies and it doesn’t give the sample size of either.

Claim:  “Research shows the forces required to deform mature connective tissue are probably impossible to create with hands, elbows or foam rollers.” (p. 5). 

Misleading. (Abstract).  Where by “research” the Hargrove means “mathematical model extrapolated from a single subject”.

Claim:  “in hockey players, strong adductors are far more protective against groin strain than flexible adductors, which offer no benefit” (p. 14).

Misleading. (Abstract) Sample size is small, and the study was of the relative strength of adductor to abductor, not absolute strength.

Claim: “Flexibility in the muscles of the posterior chain correlates with slower running and poor running economy.” (p. 14).

Accurate citation, weak study.  (Abstract) Sample size: 8.  Eight.  And it’s correlational.

[A number of interesting ideas whose citations are in books and thus inaccessible to me]

Claim:  “…most studies looking at measurable differences in posture between individuals find that such differences do not predict differences in chronic pain levels.”  (p. 31). 

Accurate citation.  (Abstract).  It’s a metastudy and I didn’t track down any of the 54 studies included, but the results are definitely quoted accurately.


Chapter 6: Pain

Claim: “Neuromatrix” approach to pain means the pattern of brain activity that create pain, and that pain is an output of brain activity, not an input (p93).

True, although the ability to correctly use definitions is not very impressive.

Claim: “If you think a particular stimulus will cause pain, then pain is more likely.  Cancer patients will feel more pain if they believe the pain heralds the return of cancer, rather than being a natural part of the healing process.” (p93).

Correctly cited, small sample size. (Source 1, source 2, TEDx Talk).

ClaimPsychological states associated with mood disorders (depression, anxiety, learned helplessness, etc) are associated with pain (p94).

True, (source), although it doesn’t look like the study is trying to establish causality.

ClaimMany pain-free people have the kinds of injuries doctors blame pain on (p95).

True, many sources, all with small sample sizes.  (source 1, source 2, source 3, source 4, source 5)

Claim: On taking some cure for pain, relief kicks in before the chemical has a chance to do any work (p98)

True.  His source for this was a little opaque but I’ve seen this fact validated many other places.

Claim: we know you can have pain without stimulus because you can have arm pain without an arm (p102).

True, phantom limb pain is well established.

Claim: some people feel a heart attack as arm pain because the nerves are very close to each other and the heart basically never hurts, so the brain “corrects” the signal to originating in the arm (p102).

First part: True.  Explanation: unsupported.  The explanation certainly makes sense, but he provides no citations and I can’t find any other source on it.

Claim: Inflammation lowers the firing threshold of nociceptors (aka sensitization) (p102).

True (source).

Claim: nociception is processed by the dorsal horn in the spine.  The dorsal horn can also become sensitized, firing with less stimulus than it otherwise would.  Constant activation is one of the things that increases sensitivity, which is one mechanism for chronic pain (p103).

True (source).

Claim: people with chronic pain often have poor “body maps”, meaning that their mental model of where they are in space is inaccurate and they have less resolution when assessing where a given sensation is coming from (p107).

Accurate citation (source).  This is a combination of literature review and reporting of novel results.  The novel results had a sample of five.

Claim: The hidden hand in the rubber hand illusion experiences a drop in temperature (p109).

Accurate citation, tiny sample size (source).  This paper, which is cited by the book’s citation, contains six experiments with sample sizes of fifteen or less.  I am torn between dismissing this because cool results with tiny sample sizes are usually bullshit, and accepting it because it is super cool.

Claim: “a hand that has been disowned through use of the rubber hand illusion will suffer more inflammation in response to a physical insult than a normal hand.” (p. 109).

Almost accurate citation (source).  The study was about histamine injection, not injury per se.   Insult technically covers both, but I would have preferred a more precise phrasing.  Also, sample size 34.

Claim: People with chronic back pain have trouble perceiving the outline of their back (p. 109). 

Accurate citation, sample size six (pdf).

Claim:  “Watching the movements in a mirror makes the movements less painful [for people with lower back pain].” (p. 111). Better Movement. Kindle Edition.

Accurate citation, small sample size (source).

Model Quality

Reminder: the model is that pain and exhaustion are a product of your brain processing a variety of information.  The prediction is that improving the quality of processing via the principles explained in the book can reduce pain and increase your physical capabilities.

Simplicity: Good.  This is not actually simple model, it requires a ton of explanation to a layman.  But most of its assumptions come from neurology as a whole; the leap from “more or less accepted facts about neurology” to this model is quite small.

Explanation Quality: Fantastic.  I’ve done some reading on pain psychology, much of which is consistent with Guide…, but Guide… has by far the best explanation I’ve read.

Explicit Predictions: Good, kept from greatness only by the fact that brains and bodies are both very complicated and there’s only so much even a very good model can do.

Useful Predictions: Okay. The testable prediction for the home-reader is that following the exercises in the back of the book, or going to a Feldenkrais class, will treat chronic pain, and increase flexibility and strength.  Since the book itself admits that a lot of things offer short term relief but don’t address the real problem, helping immediately doesn’t prove very much.

Acknowledging Limitations: low. (Note: author disputes this, and it’s entirely possible he did and I forgot).  GTBM doesn’t have the grandiose vision of some cure-all books, and repeatedly reminds you that your brain being involved doesn’t mean your brain is in control.  But there’s no sentence along the lines of “if this doesn’t work there’s a mechanical problem and you should see a doctor.”

Measurability: low.  This book expects you to put in a lot of time before seeing results, and does not make a specific prediction of the form they will come in.  Worse, I don’t think you can skip straight to the exercises.  If I hadn’t read the entire preceding book I wouldn’t have approached them in the correct spirit of attention and curiosity.

Hmmm, if I’d assigned a gestalt rating it would have been higher than what I now think is merited based on the subscores.  I deliberately wrote this mostly before trying the exercises, so I can’t give an effectiveness score.  If you do decide to try it, please let me know how it goes so I can further calibrate my reviews to actual effectiveness.


You might like this book if…

…you suffer from chronic pain or musculoskeletal issues, or find the mind-body connection fascinating.

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Epistemic Spot Check: The Demon Under the Microscope (Thomas Hager)


How much would it suck to be the guy who invented sulfa drugs? You dedicate your life to preventing a repeat of the horrors you saw in the war, succeed in that and so much more, and then 10 years later some idiot leaves a petri dish open and completely replaces you as the father of man’s triumph against bacteria.  Actually he left the lid off before you found your thing, but ignored the result until you hit it big because everyone knew you couldn’t fight disease with chemicals, until you proved you could.  It’s the ultimate silver medal.  The Demon Under the Microscope is the tale of that guy.

It’s by the same author (Thomas Hagen) as The Alchemy of Air.  It’s also set in the same corporation, and about field that was transforming from science to industry.  The writing style is similar.  I originally didn’t intend to fact check this book very hard because I already knew what to expect from the author (a little too invested in the subject but basically accurate), but the habit is too ingrained at this point and I couldn’t keep reading until I’d checked out the first few chapters.



Claim: “Domagk [the researcher] had the ability to see. He watched everything, noted slight variations, quietly filed it all away.”  (p. 18).

The wounds themselves he accepted as the results of war. But the infections that followed—surely science could do something to stop those. He focused on the bacteria, his personal demons, “these terrible enemies of man that murder him maliciously and treacherously without giving him a chance.” “I swore before God and myself,” he later wrote, “to counter this destructive madness.”  (p. 20).

Who knows but it’s pretty.  Someone in the same position as thousands of others (in this case a WW1 medic), caring more , and going to fix it (via sulfa drugs) is my moral aesthetic.  Of course there could be another surgeon in the same place with just as much care and potential who got blow up or gassed.  The Alchemy of Air prioritized poetry over provability, so I don’t entirely trust this, but I like it.

Claim: Cholera was a big problem for German soldiers.

This would be a weird thing to make up, but I’m a little confused.  There had been a cholera vaccine for over 20 years by that point.

Claim: Gas gangrene is bad.


Claim: Sir Almroth Wright created a typhoid vaccine that was deployed during WW1, saving may lives.  During WW1 he established a laboratory researching wound infections.

True.  He was also prescient enough to foresee the risk of drug-resistant bacteria.  Of course he also thought that bacteria were associated with but not the cause of disease, and that scurvy was caused by poorly preserved meat.  Being right is hard.

Claim: Doctors at the time thought that a dry wound was more resistant to infection; however dryness inhibited white blood cells and thus ultimately increased infections. They also thought wounds needed to be completely covered to prevent reinfection, but this created the ideal environment for anaerobic bacteria like Clostridium perfringens (which causes gas gangrene).

True. I was surprised to find ideal wound moistness still isn’t entirely settled, but the book’s description seems essentially in good faith.  Demon goes on to say that by the 1920s, doctors believed they were basically powerless and their job was to get the body’s own healing systems a pillow and some tea.  They took this so far that:

“A physician doing drug research was a physician taken away from patient care. There was an unsavory aspect to a physician’s developing a drug for money. There were ethical questions about testing drugs on patients. Developing new drug therapies smacked of a return to the discredited age of bleedings and purgings.”


To repeat: researching new treatments was considered distasteful at best and morally outrageous at worst.  And brain differentiation was once considered phrenology redux.  I just don’t think we’re very good at seeing where medicine is going (p40).

Claim: Section on Leeuwenhoek. 

True but missing time data.  Given that everything discussed so far happened in the range of 1890-1920, I would have have explicitly mentioned I was going 250 years into the past.  As it was, the only reason I noticed was that I recognized some of the names on the list of Leeuwenhoek’s contemporaries. The kindle edition may have made this worse.   But everything Hager actually says on Leeuwenhoek’s work in inventing the microscope seems accurate.

Claim: [crickets] (no page)

There’s no false statements, but I found the absence of discussion of the 1918 Spanish Flu epidemic puzzling.  Demon’s narrative is that seeing the horror of infected wounds in World War 1 drove Domangk to dedicate his life to preventing them.  Spanish Flu killed 5% of the entire world over the course of three years, and had a massive effect on troop movements and training in WW1.  From a military perspective it might have been more important.  We know now that the flu is really hard to vaccinate against, but at the time they didn’t even know it was a virus.  If you were a motivated medic looking for something to care about, Spanish Flu was a really obvious choice.  Demon mentions Spanish Flu in passing but not as an influence on Domangk, and that feels incomplete to me. Why gangrene in particular, when there were so many horrors happening at the time?

Claim: Streptococcus is the cause of everything bad.

True.  I knew it was possible to die from a scratch, but reading about everything strep causes really made me appreciate how few technological innovations are between us humans and mass die offs.  Strep causes childbed fever, St. Anthony’s Fire, meningitis, scarlet fever, pink eye, necrotizing fasciitis… Strep is the cockroach of human-infecting bacteria.  And for a while, all we had to do was take a pill and it was completely harmless.

Of course now we have MRSA (Methicillin-resistant Staphylococcus aureus) (whose natural habitat is the hospital, just like strep).  And multiply resistant gonorrhea.  And tuberculosis resistant to most known antibiotics.  The bad old days are on our heels, is what I’m saying.

One weird thing is I finished this book with the vague impression that sulfa drugs had saved a lot of lives but not actually knowing how many.  This article estimates that sulfa drugs led to a 2-3% drop in overall mortality, which translated to a 0.4-0.7 year increase in life expectancy.  That only covers up until 1943: presumably it had a bigger impact as distribution increased, or at least would have if penicillin had not taken over.

Overall Verdict

Pretty good, with some oversights.  Like Alchemy of Air the beginning is the best part, and if you find your attention flagging I’d just let it go.  I found the subject matter more innately interesting than Alchemy of Air but the writing a little less so.  Demon spends less time on the personal lives of the scientists, which was a selling point for my roommate but a disappointment for me.

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