There was a recent TED talk that presented some interesting research on stress. First, there was a large-scale study that asked subjects to rate the amount of stress in their lives. It also asked them whether or not they believed stress to be harmful. Then it observed mortality rates among the group over a few years. It found that the highest mortality rate (+47%) was among those with high stress and who believed stress to be harmful. No big surprise there. But the lowest mortality was not among those with low stress; it was among those with high stress, but who did not think that stress was harmful.
This is hard to understand, but a Harvard study sheds some light on why that may be. It exposed subjects to artificially stress-inducing scenarios, but only after priming them to view stress in one of two ways: Some were told that stress is physically harmful; others were told that the physiological manifestations of stress (increased heartbeat, rapid respiration, sweating, etc.) are simply the body’s way of preparing you to meet a challenge, and that it is a good thing. The “stress is bad” group experienced vascular constriction during stress, which is a dangerous condition. The “stress is good” group experienced all of the usual stress responses, but without the vascular constriction.
The upshot of the talk was that, ironically, what makes stress harmful is believing that stress is harmful. Viewing stress as an ally rather than an enemy makes sense to me.