Why Zebras Don't Get Ulcers: The Acclaimed Guide to Stress, Stress-Related Diseases, and Coping

by Robert M. Sapolsky

Back to stress turning off salivation, an inhibition mediated by the sympathetic nervous system. What if you have to salivate for a living, if you are, say, an oboe player? Big audition comes along, good and nervous and—disaster—no spittle. Thus, many reed musicians wind up using drugs like beta-blockers that block the action of the sympathetic nervous system in order to slobber just in time for the big arpeggio.

Ol’ King Fred was quite the budding scientist. Then there was the time he got interested in digestion. Frederick wondered whether digestion was faster when you rested after eating or if you exercised. He had two men brought from his prison, fed identical and sumptuous dinners, and sent one off to nap afterward, while the other went for a strenuous hunt. That phase of the experiment completed, he had both men returned to his court, disemboweled in front of him, and their innards examined. The sleeper had digested his food better.

The other region supplies new neurons to the olfactory system; for some strange reason, neurons that process odors constantly die off and have to be replaced. It turns out that there is a huge burst in the production of those new olfactory neurons early during pregnancy. They are fully on line just around the time of birth, and the scientists who discovered this speculated that these new olfactory neurons are tagged for the task of imprinting forever on the smell of your offspring (a critical event for mothers of most mammals). And what happens early in pregnancy, when those new olfactory neurons are showing up, but not quite making sense yet? I bet this has something to do with the famed nausea of pregnancy, the food aversions and olfactory sensitivities. This has nothing to do with stress, but it is too cool not to mention.

In the previous section, we added your hippocampus to that list of places that are spoon-fed energy with the onset of a stressor. It seems like that would be a clever area to continue to stoke, as the stressor goes on. Why should glucose delivery eventually be inhibited there? Probably because, as time goes by, you are running more on automatic, relying more on the implicit memory outposts in the brain to do things that involve reflexive movement—the martial arts display you put on to disarm the terrorist or, at least, the coordinated swinging of the softball bat at the company picnic that you’ve been nervous about. And thus, the decreased glucose delivery

An additional pathology, for those who are really trivia fans when it comes to stress-related disease, is “stress-related alopecia areata.” This is the technical term for that extraordinary state of getting so stressed and terrified by something that your hair turns white or gray over the course of days. This really does occur. The annotated notes at the end of the book detail the surprisingly frequent intersection of alopecia areata with law, history, and geopolitics.