Why Zebras Don't Get Ulcers

Summary

In Why Zebras Don't Get Ulcers, Robert Sapolsky explains the neurobiological underpinnings of how stress works in the human body. He also looks at the evolutionary history and the (mostly negative) medical effects that stress can have on our lives and how we can protect ourselves from those.

In characteristic Sapolsky fashion his analysis is detailed and complex, showing the interlocking details of different levels of abstraction in biology. This idea of different levels of time that have an effect on events is something he also covers in detail in his other book Behave.

Stress, especially if prolonged in time, can have very negative effects on our mental and physical health. He uses the example of zebras—who experience intense but short bursts of stress to escape predators and then return to a calm state—as a contrast to humans, who often experience long-term, psychological stress. That's why zebras don't get ulcers.

The thing is: a fight or flight response is good in the short term, because it helps to deal with imminent threats. However most of our modern day stressors are not short term in nature, like a lion chasing after you... Instead stressors like low income, a bad situation at work or problems with our family can persist over years and this makes the effects of stress become toxic and detrimental to our health. This problem gets worse because Humans have metacognition and that makes us particularly susceptible to prolonged, ongoing stress. We can worry about things that don't even exist or only might happen in the future.

The difference lies therein: acute vs. chronic stress–acute stress is manageable and even adaptive, while chronic stress can permanently damage you.

Stress has a series of effects on the body:

• it suppresses the immune system in order to have more energy to fuel muscles
• it messes up the digestive system, contributing to issues like ulcers or irritable bowel syndrome
• it contributes to high blood pressure and cardiovascular disease in general
• it disrupts the reproductive axis and leads to issues like infertility and reduced libido
• it negatively impacts memory, learning, and mood, and increases the risk of mental health issues

Individual differences in personality and perceived control impact stress levels directly. Stress is more harmful if we feel like there is no way out. Another way to buffer against stress is a healthy social network. Friends and peers help us to manage stress a lot better, which coincidentally is one of the reasons why loneliness is so bad for us.

We need coping strategies against stress to protect ourselves from its harmful effects:

• exercise
• social connection
• mindfulness (and meditation)
• cognitive reframing

In summary this book tries to help readers recognize the pervasive influence of stress and give them strategies to cope with chronic stress to reduce its harmful effects. As such it is similar to other books like Why We Sleep, that take a look at commonly underestimated causes of bad health and tries to help people be aware of them and suffer less.