Why Zebras Don’t Get Ulcers: Chapter 1
In Chapter 1 of Why Zebras Don’t Get Ulcers, Robert Sapolsky draws a contrast of causes of death today and throughout most of human history. For example, in the early 20th century the main causes of death were infection, such as the flu or tuberculosis. If you were female you worried about dying from child birth. Today, it’s cancer and heart disease. Why? Well, one of main factors is psychological stress. Stress can make us sick. That’s what this book is all about – what stress is, different types of stress, and why its bad for us.
To start, some initial concepts.
This book deals with chronic psychological and social stress. The reason zebras don’t get ulcers (am I answering this too soon?) is because they only have to deal with acute physical stressors, whereas people are stressed all the time. We worry about getting the kids dressed in the morning, the traffic on the way to work, the deadline at work, the economy, and so on. There are enough things to worry about that you can be stressed all day, everyday. Zebras only have to worry about the lion for a few minutes every once in a while. Basically, our bodies are designed to handle these short term physical stress well, but not chronic psychological stress.
Stress knocks us out of homeostasis. A stressor is anything that knocks us out of homeostasis and the stress response reestablishes homeostasis. With that said, Sapolsky prefers the term allostasis. How these two differ isn’t a big deal for a simple summary. Read the book if you must know.
When stress goes on for two long, the stress response can be more damaging that the stressor itself. All the things that occur during the stress response, and are good for the short term, hurt us if turned on too often. For example, during a stress response your body mobilizes glucose to provide the body with energy. This increases blood sugar. What happens if blood sugar is constantly elevated? Diabetes. Another example is blood pressure. Increasing blood pressure is good when you have to run from a lion, but constantly elevated blood pressure can lead to cardiovascular disease.
There are other examples given and we will talk about those (and the ones already mentioned) in more detail when I get to the appropriate chapter. That’s it for chapter 1, see ya next time.