 Our minds aren't passive observers, simply perceiving reality as it is. Our minds actually change reality. In other words, the reality that we will experience tomorrow is in part a product of the mindsets we hold today. Our mindsets come from many places. Our mindsets about stress come from our upbringing and the words of encouragement we may or may not have heard. Our mindsets about what it means to be fit and beautiful. They are a product of the cultures that we live in. Every day, marketing and advertising shapes our mindsets about what is good, worthy or exciting to eat, and influential doctors and health scientists have an uncanny authority to craft how healthy we expect ourselves to be. I study mindsets like these and how they impact our physical health. Thousands of clinical trials have shown that simply taking a sugar pill under the impression that it's a real medication can reduce not just our anxiety and pain, but lower our blood pressure, boost our immune system, placebo's work not just by making us say we feel better, but by triggering, activating a whole host of specific neurobiological effects. Holding the mindset that a pill or medication will relieve your anxiety, for example, activates the body's parasympathetic nervous system. The power, of course, is not in the sugar. The power comes from the social context that shape our mindsets in ways that activate our body's natural healing abilities. And the dirty secret of all clinical trials is that once the trial is said and done, the placebo effect remains, not as something to be subtracted or ignored, not as some magical or mysterious response to a sugar pill, but the psychological and social foundation, the support system on which the total effect of any drug or therapy is placed. These principles apply to health behaviors as well. Hotel room attendants, for example, get a substantial amount of physical activity throughout their day of work, but typically don't think of their work as good exercise. What we found in our research is that a simple shift in mindset from the mindset that their work is just work to the mindset that their work is good exercise produces physiological changes in the body. After just four weeks of adopting the mindset that their work is good exercise, hotel room attendants lost weight and lowered their blood pressure by 10 points. What this means is that objective health benefits, things like a healthy heart and a healthy weight depend not just on what we're doing, but what we think about what we do. The same is true for food. In this study, we gave people the exact same milkshake, but with two very different labels. What we found is that when people thought they were in the mindset that the shake was indulgent and caloric, their body's hunger hormone, ghrelin, dropped at a three-fold rate, speeding up their metabolism and leaving them feeling physiologically satiated. So how does this work? How do mindsets influence our health? Take these two mindsets about stress, for example. The truth is that both of these mindsets are possible, but the rub is that the mindsets we choose to hold influence the outcomes that will result. Mindsets change what we pay attention to. Mindsets change what we're motivated to do. Mindsets change how we feel and expect to feel, and mindsets change what our bodies are prepared to do. Through cascading effects on these psychological, behavioral, and physiological mechanisms, mindsets can create the reality that's implied. In other words, having the mindset that stress is enhancing, ironically, is what makes those enhancing effects more likely. So as influential leaders and decision makers, it's essential to recognize that mindsets are not peripheral, but central to health and behavior. If we truly want to tackle the diseases and crises of our time, we need to more effectively acknowledge and leverage the power of mindset.