In 2011 Carney travelled to meet Dutch fitness guru Wim Hof in Poland on an assignment from Playboy with the intention of exposing him as a charlatan. Hof claimed to be able to teach a meditation technique that would allow people to consciously control their body temperature and immune systems. The claims were similar to those made by Michael Roach. After a week studying the method, however, Carney had to reevaluate everything he thought about gurus. Within a week he learned how to perform similar feats as Hof, including hiking up a snow covered mountain wearing just a bathing suit. His book, What Doesn't Kill Us, continues the journey by linking evolutionary theory and environmental conditioning with the Wim Hof Method. He interviews US Army scientists who are trying to find ways to make soldiers more effective in extreme environments, the founders of the outdoor workout movement the November Project, legendary surfer Laird Hamilton and endurance runner Brian MacKenzie. Carney ends his journey by climbing up to the top of Mount Kilimanjaro, most of the way, wearing just a bathing suit.