Stress Hormones, Heart Rate Variability, and Resilience in Special Forces
Resilience is broadly defined as the ability to preserve healthy physical and psychological functioning in the face of chronic or traumatic stress. Exposure to chronic and traumatic stress signals the autonomic nervous system to activate the hypothalamic pituitary adrenal (HPA) axis, which triggers the secretion of stress hormones, cortisol, and dehydroepiandrosterone (DHEA), from the adrenal cortex, which is associated with a heightened ability to recruit valuable physiological resources to respond effectively to the stressor. However, prolonged exposure to cortisol can have deleterious effects on the brain and lead to negative physical and psychological outcomes. Antiglucocorticoid effects of DHEA and DHEA-sulfate (DHEA-S) appear to counter the long-term negative effects of cortisol and bolster resilience. The autonomic nervous system also regulates heart rate variability, which also appears to be associated with resilience in the face of environmental stressors. The present studied explored the ratio of DHEA and DHEA-S to cortisol and heart rate variability (HRV) as indices of resilience. Twenty-eight members of the U.S. Army National Guard Special Forces completed resilience questionnaires, provided blood-based DHEA and saliva-based cortisol, and underwent HRV measurement while interacting with a stress inducing virtual environment. Significant relationships and trends toward significance were observed between both biomarkers for resilience and aspects of resilience. The present study provides evidence that both biomarkers can be used as indices for resilience to stress.
Doctor of Philosophy in Clinical Psychology (PhD)
Amano, Stacy S.
Stress, Hormones, Heart rate monitoring, Stress management, Resilience