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

by Robert M. Sapolsky

So sometimes the problem in aging is not enough of a stress-response. Predictably, in some realms, the problem is too much of a stress-response—either one turned on all the time, or one that takes too long to turn off at the end of a stressor.