What Is Stress?
It's not as if you've never experienced stress. Each of us encounters stress in one form or another on a daily basis—in fact, we encounter stress multiple times during every day of our lives. Even more important than the things that cause us to experience stress, however, is our body's ability to cope with that stress. We're going to talk about the physiological and biochemical responses of your body to the things we identify as "stress" and about how you can customize your approach to dealing with those internal chemical cascades.
Let's start off with a tidy definition of stress. For our purposes we'll define it as "what you feel when life's demands exceed your ability to meet those demands." With that said, it is important to acknowledge that everybody has a different capacity to effectively cope with stress and, thus, to "perform" when stress is encountered. Even those rare individuals who have a high tolerance for accommodating stressful situations ultimately have a breaking point. Add enough total stress to anybody and performance suffers.
Many of the top stress researchers in the world have made the interesting distinction between the type of stressors faced by our cousins in the animal kingdom (short-term or acute stressors) and the kind we modern humans routinely face (longer-term and repeated chronic stressors). To compound our problems as "higher" animals, we are plagued not only by physical stressors but also by psychological and social stressors. Some of those psychological stressors are quite real (like your monthly rent or mortgage payment), while others are purely imaginary (like the stressful encounters that you imagine you might have with your boss, coworkers, kids, or others). How do you like that? Not only has our large, complex, and supposedly "advanced" brain developed the capacity to get us out of a whole lot of stressful situations, but it has also developed the capacity to actually create stressful situations where none existed before.
Robert Sapolsky, author of perhaps the best (and most readable) book on the subject of stress physiology, Why Zebras Don't Get Ulcers (see Resources, located in the back of the book), uses the whimsical examples of zebras being stressed out by lions and baboons being stressed out by each other to illustrate the fact that short-term (acute) periods of stress are vital to survival (at least from the zebra's perspective). From his many examples, we come to learn that whereas acute periods of stress are necessary, a chronically elevated stress response is detrimental to long-term health in a variety of ways. Following the lead of Dr. Sapolsky and virtually every physiology professor who teaches about the fight-or-flight response, this book will also employ numerous examples of zebras, monkeys, and baboons to illustrate concepts related to stress physiology.