Chapter 1: Why Don’t Zebras Get Ulcers?

This book is focused on stress, stress-related disease, and the mechanisms of coping with stress.

Our personalities, thoughts and feelings reflect and influence our bodies. Stress can make us sick: many of the damaging diseases of slow accumulation can be either caused or made worse by stress.

Stress for us vs stress for zebras:

• For us: deadlines, traffic, money worries, relationships… We can generate all sorts of stressful events purely in our heads.
• Zebras: serious physical injuries, predators, starvation… For animals, the most upsetting things in life are acute physical crises.

For the vast majority of beings on this planet, stress is about short-term crisis. It is only damaging once it’s provoked chronically.

Stressor and stress response:

• For zebras: A stressor is anything in the outside world that knocks you out of homeostatic balance, and the stress response is what your body does to reestablish homeostasis
• For us: A stressor can also be just the anticipation of something that would knock us out of our homeostatic balance

Hans Selye: through research with rats, he came to the conclusion that if stressors go on for too long, they can make you sick.

• He developed a three-part view of how the stress-response worked:

1. Initial (alarm) stage: a stressor is noted
2. Adaptation, or resistance: comes with the successful mobilization of the stress-response system and the retainment of allostatic balance
3. “Exhaustion”: where stress-related diseases emerge

Allostasis: the modified, modernized version of the homeostasis concept:

• While homeostasis states that there is a single optimal level, number, amount for any given measure in the body, allostasis recognizes that this optimal level changes through situations.
  • Example: the ideal blood pressure when you’re sleeping is likely to be different than when you’re ski jumping.
• Homeostasis implies that you reach that ideal set point through some local regulatory mechanism, whereas allostasis recognizes that any given set point can be