These findings further show that hormones released during an acute stress response may help prepare the immune system for a potential challenge, such as wounding or infection, with stress perception by the brain serving as an early warning signal" (Bonner 1999).

             Effects of acute and chronic stress.

             It is possible that stress can be relatively neutral. In experiments with exposing dogs to stressful conditions, including administration of saline infusions, researchers discovered in the 1980s that when stress and saline were discontinued, the blood pressure that had risen receded, and no pathological change in hypertension was recorded in the test animals. "Although one may speculate that longer exposure might lead to a permanent state of hypertension, the fact remains that we still do not have a clear-cut demonstration of chronic hypertension produced by a stress paradigm" (Shapiro 1996, 18).

             That may have been true in 1996, but in 2004, McEwen reported a connection- a connection, moreover, that is attended by a constellation of other factors that seem to be the result of excessive stress. McEwen noted that acute stress may promote immune function "by enhancing movement of immune cells to places in the body where they are needed to defend against a pathogen; yet, chronic stress suppresses the immune function and uses the same hormonal mediators to suppress immune function" (2004, 3).

             Abdominal obesity is a central concept regarding the transition of useful stress, the sort that helps protect against disease pathogens, to damaging stress, or the sort of stress that enhances the ability of the body to create disorders such as, notably, high blood pressure (hypertension), and other cardiovascular damage. McEwen explains it all in terms of states called allostatic and homeostatic states. The homeostatic state is concerned with those systems essential to life. And allostatic state, on the other hand, "results form an imbalance of the primary mediators" of the metabolism.