So far, in our discussion, we have emphasized how the body has a fairly generalized stress response to any stressor. A physical danger or a purely psychological stress and the response of the body is pretty much the same. Hidden in this generalization are many subtleties. Obviously, a lot of the technical details are beyond the scope of this treatise. However, we will look at some of the aspects that will give an idea of the complications.
The first simple point is that not all species respond to stressors in the same way. Though animals are used in the laboratories, humans do not necessarily have the same response.
Another complication has to do with the pattern of stress responses to different stressors. Scientists look at the pattern of release of the hormones for a particular stressor and they term it the ‘hormonal signature’ of a particular stressor. The basic hormonal system outlined in the previous section holds true for massive physical stressors. Subtle stressors will not have the same hormonal effect—for example, public speaking may be stressful but will obviously not elicit the same stress response as some grave physical danger.
Typically, scientists have found that a high degree of sympathetic activity is found in the case of anxiety and vigilance while higher secretions of glucocorticoids mark depression like symptoms. Similarly, epinephrine and norepinephrine are not released in response to all stressors.
We have made the point that the stress response was crafted by millions of years of evolution and is ideal for dealing with life-threatening physical stressors encountered by our ancestors. In that context, it is fair to question the role of glucocorticoids. We mentioned earlier that glucocorticoids back up the action of epinephrine over minutes and hours. So, how many chases in the wild or sprints across the grasslands go on for hours? Typically, such contests are over in five to ten minutes. For example, a cheetah can sprint for only eight or ten minutes before it gives up.
Then, of what use is the action of glucocorticoids? This is an important area of research and a number of theories have been proposed. The best explanation so far is that the glucocorticoids are not really a stress response but they help mediate the recovery from the stress response and they help the body prepare for the next stressor. These are tentative theories backed up by some experiments—so stay tuned for more developments in this field.
One final note (the point that gives us a fay of hope for dealing with stressors): Stress response depends on psychological factors and two identical stressors can cause widely different responses depending on the psychological context. It is fascinating that the physical response of our body to a stressor can be controlled by our mind or by the way we perceive things. This is a very powerful concept and we will explore this topic further in the following chapters.
To conclude, I will emphasize the main thesis of this book—in spite of some differences in response to various stressors, the major stress response is pretty consistent for a wide variety of stressors.