Why Zebras Don't Get Ulcers: A Book Review

Ok. This book grabbed my attention with its title: Why Zebras Don't Get Ulcers. This 2024 work in neurobiology and psychology by Robert Sapolsky demonstrates the deep relationship between the mind and the body. At its core, the book examines how, in the contemporary world, stress responses in humans can contribute to chronic illnesses. 

The author begins by comparing the ways in which stress affects people and animals differently. For animals like zebras, stress comes from severe physical emergencies. The zebra's nervous system initiates the "fight-or-flight" reaction when, for example, a lion starts chasing it. Hormones like adrenaline and glucocorticoids are secreted in large quantities as a result. These substances halt long-term self-maintaining processes such as digestion, growth, and reproduction and, in order to respond to the immediate threat or stress, rapidly redirect energy to the muscles and senses. The zebra's body returns to normal equilibrium after the threat has passed.

Humans, on the other hand, are different in that, one, we do not face zebra-esque physical threats often, and two, physiological reactions are produced by psychological factors as well (ex. worrying). Unlike most animals, humans are mentally and psychologically concerned with all kinds of issues, such as careers, mortgage payments, relationship problems, deteriorating health, etc. That is, a tense encounter with a boss and a predator in the wild causes the same effect for humans. And, while a predator-prey encounter in the wild is temporary, we keep our stress response activated for months or years because stressors are frequently chronic rather than acute. If you continuously mobilize energy but never truly "run for your life," your body eventually starts to malfunction, according to Sapolsky.

The physiological effects of long-term stress hormone levels are as follows:

• Cardiovascular System: Hypertension can be from ongoing stress. Persistently high blood pressure damages the blood arteries, causing plaque to accumulate and raising the risk of heart attacks and strokes.
  

• Metabolism: The body cannot correctly store nutrients due to constant energy mobilization, which can lead to Type 2 diabetes and "stress-induced" weight distribution, especially belly fat.
  

• Immune System: Although stress initially increases immunity, long-term exposure to glucocorticoids eventually lowers it, increasing the body's susceptibility to infections and delaying the healing process.
  

• The Brain: Perhaps most startlingly, Sapolsky describes how long-term stress can harm the hippocampus, the part of the brain in charge of memory and learning, and may worsen clinical depression by lowering serotonin and dopamine levels.

Sapolsky further argues that those at the bottom of a social hierarchy frequently have greater baseline levels of stress hormones and worse health outcomes (based on his research on baboons, which seems to be his “thing”). For people, this corresponds to the socioeconomic status (SES) levels. In a nutshell, stress-related illness is frequently caused by feelings of poverty or lack of control over one's life, future, and opportunity.

Sapolsky concludes that, though humans cannot eliminate stress, it can, and should, be controlled for better health. Important elements in developing coping mechanisms consist of the following:

• Predictability and Control: Having a sense of agency and anticipating the arrival of a stressor.
  

• Social Support: One of the best defenses against the physiological impacts of stress is a strong social network.
  

• Finding constructive ways to "expend" the released energy is one way to find outlets for frustration.

Ultimately, the author warns us to be mindful of the cost of mental worries (anxiety, fear, depression, etc.) and calls for a change in the way we organize our lives and communities to avoid 'worry lions.' The recommendations are, well, not revolutionary or impressive, so it's a sort of let-down.

Although the book contains a lot of technical jargon and describes intricate processes over its 400 pages, it is still very readable and comprehensible for average Joes. I’m not 100% convinced that you need this book, but it can be quite enjoyable.