LAUSR

Stress is everywhere. In evolutionary terms, given the range of stressful environmental challenges faced, the human race could not have evolved without developing successful physiological strategies to cope with and overcome potentially life-threatening challenges. The need for a robust response to an acute stress is well-established. Not only do we as individuals have to accommodate ourselves successfully to a dynamically changing environment on a daily basis, the course of history itself has been determined by those who have mounted the most successful responses to aggressive challenges on a grand scale. Much of the scientific literature (and almost all of the popular press) has focused on the negative effects of stress on immune functions and the deleterious consequences on health. There is a considerable body of evidence in animals and humans which demonstrates that chronic stress exerts a negative influence on general health and specific disease processes. But what is often overlooked are the positive effects which acute stressors can exert on our immune system and consequently on our health. It would seem to be an evolutionary imperative, that positive responses to danger should influence long-term survival and that this implies development of a more robust species. It does not make any evolutionary sense that all stress should be bad. If it were, proto-human life would have died out soon after it crawled out. Positive effects of acute stress on immune responses were reported in early research into psychoneuroimmunological interactions (PNIs) (Blecha, Barry, & Kelley, 1982) and the literature has been regularly reviewed (Dantzer & Kelley, 1989; Dhabhar, 2009, 2014; Glaser & Kiecolt-Glaser, 2005). Dhabhar (2018) has proposed the concept of the “stress spectrum” to differentiate the beneficial effects of acute stress from the harmful effects of chronic stress. So, it is very apposite to touch on this subject now to highlight that insufficient research is being conducted into these links in humans. The basic neuroendocrinology of the major stressmediating pathways, the hypothalamo-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS), is understood. The impact of the major stress hormones catecholamines and glucocorticoids on promoting survival of a healthy and robust human population is not. We need to learn much more about the positive effects of stress on health if we are to understand how we have survived and thrived. The eminent scientist and clinician George Solomon (1997) has provided us with a roadmap which we can follow to guide research into the links between a stressor and a health/illness outcome with underlying neuroendocrine/ immune mechanisms. It is worth quoting at length from his 1997 paper: