Review: What Doesn't Kill Us

What Doesn't Kill Us suffers from a fundamental problem with science as explained by English majors, which is that the plural of anecdotes is not data. The thesis of the book is that the Wim Hof method of continual exposure to cold temperatures along with a certain method of breathing exercises allows you to control your immune system consciously, improve your fitness, and allow you to (amongst other things) summit Kilimanjaro in 2 days without altitude acclimation (the climax of the book).

Early on in the book, there's a pursuit of a theory that brown adipose tissue (BAT, or Brown Fat) is the mechanism by which these metabolic effects work. But we quickly discover that that's a dead-end:

just under 2 weeks cold exposure almost reversed the symptoms of diabetes. As one of the pioneering researchers on BAT, van Marken Lichtenbelt predicted that the metabolic changes would come with a corresponding increase in their BAT levels, but when results from the PET/CT came back it turned out that most of men had the same levels of BAT as when they entered the study. Cold exposure had changed the men’s underlying condition, but the lightning that van Marken Lichtenbelt was trying to bottle must have come from somewhere else. (pg. 102)

After that brief flirtation with science, Carney gives up and goes whole hog into the multiple-celebrity theory of scientific proof.  We get a cameo by Orlando Bloom practicing this, an exposition of Laird Hamilton's adoption of the Wim Hof techniques, an exploration of the new "tough mudder" style of obstacle course racing, and the aforementioned Kilimanjaro record-setting summit.

All of these are effectively small group studies, usually without controls, and definitely without statistical success. Every one in the sample sizes is self-selected, and though some of the anecdotes are impressive (an arthritic blacksmith regains control of his muscles, a Parkinson's sufferer halves the dosage required to keep his Parkinson's under control), they fall into the "ok, if you're this desperate, you might as well try this. You've got nothing to lose" category.

There's some evidence that our climate controlled environment might not be great for us, and that it's good to get exposure to nature, but there's no systematic teasing out of how much exposure makes a difference, and how this folklore is better than your mom's "you'll catch a cold" folklore.

As an entertaining piece of journalism the book's fine. It's also a decent airplane read. If you're desperate for a solution to your immune problems it might be worth looking into the method, but the entire account is far from scientific.