Can repeated psychosocial stress erode stress resilience?

Repeated psychosocial stress prevents the body from returning to a homeostatic baseline, keeping major stress-response pathways constantly engaged and gradually wearing down physiological defenses.

Autonomic and endocrine activation

• Persistent physiological arousal: Repeated psychosocial triggers keep the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic-adrenal-medullary (SAM) system continuously active. This chronic activation is characterized by flattened diurnal cortisol rhythms, a blunted cortisol awakening response (CAR), or systemic hypocortisolism.
• Autonomic rigidity: Ongoing stress suppresses parasympathetic activity (vagal tone) while driving sympathetic overdrive. This state is marked by reduced heart rate variability (HRV), which compromises cardiovascular flexibility and emotional regulation.

Mechanistic drivers of resilience erosion

• Glucocorticoid receptor resistance (GCR): Prolonged exposure to high cortisol levels down-regulates and desensitizes glucocorticoid receptors. This resulting resistance prevents the crucial negative feedback mechanism required to terminate the stress response, leading to persistent biological vulnerability and systemic inflammation.
• Allostatic overload: The cumulative wear and tear of sustained sympathetic dominance and HPA dysregulation represents a state of allostatic overload. This biological rigidity strips the body of its dynamic flexibility, rendering it progressively less capable of adapting to subsequent stressors.

Bottom line

• Repeated psychosocial stress sustains HPA axis and autonomic activation, driving glucocorticoid receptor resistance and autonomic rigidity that progressively erode physiological and psychological resilience over time.