Why Zebras Don’t Get Ulcers by Robert M. Sapolsky Owl Books (Henry Holt) 2004 Whenever I reread Robert Sapolsky’s classic book “Why Zebras Don’t Get Ulcers”, I learn a lot that’s new. That’s because he updates the book every few years with up-to-the-minute research and scientific findings. Now in its third edition, the book keeps getting fatter with new information and insights. Dr. Sapolsky infuses his writing with wit and humor that makes you forget you’re reading very detailed science. Robert Sapolsky is a professor of biology and neurology at Stanford University. He is also a Research Associate with the Institute of Primate Research at the National Museum of Kenya. He divides his time between California academia and his field work in Africa studying baboons and other primates. The book blends both perspectives in a fascinating way. Sapolsky shifts back and forth to show the many similarities and important differences between humans and members of the animal kingdom. While the physiology of the stress reaction is the same for all living beings (it’s the fight or flight response that allows us to react quickly to life-threatening situations), there are key points of contrast. For example, zebras (and other denizens of the African Savanna such as lions and baboons) mount a stress reaction when they’re confronted with danger. but they turn it off when the threat has passed. We, in our so-called advanced society, experience chronic stress because we turn on our stress reactions too often and then allow them to go on for too long. Another key difference is that animals experience stress when they’re physically threatened. Most of our stress is psychological. Animals live in the present moment. They don’t worry about the future, dwell on the past, nor spend excessive amounts of time worrying about what other people think of them. Much of our stress comes from our (often over-used) ability for self-reflection. The first two chapters deal with stress theory and physiology. Then there are separate chapters dealing with the effect of stress on the heart, growth, metabolism, digestion, sex and reproduction, the immune system, pain, memory, sleep, aging,, depression, and how personality and temperament are related to stress. There’s something here for everyone, The book is filled with fascinating information and factoids that you can trot out at your next cocktail party. For example, did you know that stress makes about two thirds of people hyperphagic (eating more) and the rest hypophagic (eating less)? Or that the average mammal (including humans) expends 10-20% of their energy on digestion? He cites recent work by Shelley Taylor, a psychologist at UCLA, making the case that the physiology of the stress response is different in females. Where men respond with the fight-or-flight reaction, women take care of their young and seek social affiliation, a tendency that she calls “tend and befriend”. Oxytocin seems to be the hormone responsible for this socializing tendency in women. In his new chapter on stress and sleep, Sapolsky notes that not getting enough sleep is in itself a source of stress. This is one of the most accessible and enjoyable books on science that I’ve ever encountered. I found it hard to put down and a delight to pick up. Do yourself a favor and read it.