One of the most powerful lessons I learned from this interview is that Keith is a relentless self-experimenter. Everything he talks about in this interview he has tested on himself. What of the most effective ways to learn is to learn the hard lessons from other people so you don't have to learn them yourself the hard way. Keith offers a lot of wisdom here for you to absorb.Keith suggested the book "The Upside of Stress" to me on our twitter exchange. This book basically says that the conventional wisdom that stress is harmful is totally crazy. Instead, stress is an inevitable part of being human and that the stress response can be a huge tool for growth when you view stress not as a threat but as a challenge. We talk a lot about this.We also talk a lot about the evidence behind High Intensity Interval Training and how it can lead to feeling better throughout your life. Keith gives a lot of wisdom about his own HIIT practice and how it helps him to stay productive throughout the day.