The other side of the coin: blunted cardiovascular and cortisol reactivity are associated with negative health outcomes.

A cornerstone for research into the link between stress and health has been the reactivity hypothesis; cardiovascular reactivity to psychological stressors, if prolonged or exaggerated, can promote the development of cardiovascular disease. However, it has recently been argued that low or blunted reactivity is also associated with negative health outcomes. As such, in this special issue we present further evidence implicating that cardiovascular and stress hormone responses to acute stress at the other end of the response spectrum can also be considered a pathway to ill health. In this introductory article, we explore and review the origins of and potential mechanisms underlying blunted responses to acute stress. In so doing, we aim to highlight: what is currently known regarding this new conceptualization of the reactivity hypothesis; the potential explanations for blunted reactivity; the pathways underlying associations with health outcomes; and where this field is headed in terms of developing our understanding of the link between reactivity and health.