I have been lent a book called Why zebras don’t get ulcers, the acclaimed guide to stress, stress-related diseases, and coping, by Robert M. Sapolsky.
I am on chapter one; here are a few snippets I have learnt from it so far:
“We are now living well enough and long enough to slowly fall apart” says Sapolsky.
Many of todays diseases where damage accumulates slowly (cancer, cardiovascular disease, cerebrovascular disorders) can be caused or made very much worse by stress. Our individual vulnerability to stress related disease depends on psychological characteristics, level of emotional turmoil, and even our position in society.
We in the Western World suffer from psychological and social disruptions rather than the extreme stress of hunting for food, being hunted or being starving; this sustained psychological stress is a recent phenomenon mostly limited to humans and other social primates.
The crux of the book is summarised in this quote –
“if you are that zebra running for your life, or that lion sprinting for your meal, your body’s physiological response mechanisms are superbly adapted for dealing with such short-term physical emergencies. For the vast majority of beasts on this planet, stress is about a short-term crisis, after which it’s either over with or you’re over with. When we sit around and worry about stressful things, we turn on the same physiological responses – but they are potentially a disaster when provoked chronically. A large body of evidence suggests that stress-related disease emerges, predominantly, out of the fact that we so often activate a physiological system that has evolved for responding to acute physical emergencies, but we turn it on for months on end, worrying about mortgages, relationships and promotions”.
One of the main differences in animals and humans is that humans feel stress in response to the expectation of future events, whereas animals can’t get stressed about possible future stressors (unless in the next minute, e.g being eaten). So it is our anticipation of something bad happening that causes us stress.
Regardless of the stressor, the physiological response is the same – energy rapidly mobilised, energy storage stopped, secretion of certain hormones, the inhibition of others, increased heart rate, blood pressure and breathing rate to transport nutrients and oxygen at greater rates. During stress, growth and tissue repair is curtailed, sexual drive decreases, immunity is decreased, pain perception blunted, some aspects of memory improve, senses become sharper. At the beginning of the twentieth century physiologist Walter Cannon, coined the term ‘fight-or-flight’ response to describe these symptoms.
Whilst I continue reading this fascinating book I may write another blog once I gain more insight into why zebras don’t get ulcers.