I just watched an amazing National Geographic special called “Killer Stress: Why Zebras Don’t Get Ulcers”. It’s definitely worth watching if you can find it. The show deals with they physical ramifications of stress on the human body by looking at how animals deal with stress. The program is based on the work of Dr. Robert Sapolsky who is a Professor and researcher at Stanford University. He explains that in nature, stress occurs for a very good reason: to save an animal’s life.
Zebras and Stress
Dr. Sapolsky first takes us through zebras and how they deal with stress. In the wild, zebras get stressed primarily for one reason: a predator, such as a lion, is chasing them because it wants to kill them and eat them. In this case, stress is a good thing, a very good thing. It causes all of the zebra’s resources to be channeled into one thing: keeping the zebra alive. What’s happening internally is that the zebra is temporarily knocked out of homeostatic balance. The definition of homeostasis is: balance or equilibrium, typically between the chemical environment of the body and the external environment. This means that the normal day-to-day functioning of the body stops, and anything that is not immediately pertinent to keeping the zebra alive is abruptly halted. When a lion is chasing you, it’s no time to ovulate! It is a time to run like hell and get away. So the body is flooded with adrenaline and noradrenaline to help the zebra run faster and harder.
But the amazing thing about the zebra is what happens after the chase (if it’s not eaten that is!). It goes back to normal. All of its systems return to a homeostatic balance as if nothing has happened. Now it can ovulate and do all of the things that it needs to do for the majority of the time it’s alive. Only for a very small percentage of a zebra’s life is it actually being chased by a lion. And when it’s not being hunted, it just lets it all go. It doesn’t sit there and dwell on the fact that a lion just chased it to make zebra meat of it. He doesn’t keep talking to his friends about “what a close call” that was and how “he just can’t get over it.” And so the zebra is not living in a state of chronic stress. It is aware of it’s surroundings, but it is not in a state of stress unless an immediate threat exists. There are no “perceived” or future threats that it is stressed over. Seems like a perfectly natural and healthy way to live.
Humans and Stress
It seems that humans have a lot to learn from zebras when it comes to stress management. Unfortunately many people today live in a state of chronic stress, despite the relatively safe environments that most of us live in. We no longer have to run from lions or worry about being crushed by a mammoth. And in the absence of real life threatening situations, we have created ways to stress ourselves. The body cannot differentiate between different types of stresses, so whether our lives are in peril or we are just pissed off because someone cut us off on the freeway and we’re seething and yelling, the body interprets these things the same. And unfortunately for humans, we are not good at letting the stress go and returning to a normal state. We dwell on things. In fact, we dwell on things that have already happened, and we dwell on things that may happen. Dwelling on things is some people’s full time job.
That means that often times humans are in a state of constant stress. And as we’ve learned, when we are stressed, our bodies’ chemical systems are off balance. One of the major systems that suffers is the immune system. And when the immune system is down, we get sick. Tomorrow we’ll talk more about the physical effects of stress on the human body and what can be done.