Chapter 10: Stress and Disease

Stress is conceptualized as a perceived threat that disrupts homeostasis and activates integrated biological responses, evolving from Hans Selye's foundational model of the general adaptation syndrome through three progressive stages of alarm, resistance, and exhaustion. Contemporary frameworks of allostasis and allostatic overload better explain how repeated or chronic activation of stress systems imposes cumulative wear on the body, accelerating aging and disease susceptibility. The chapter details three primary stress pathways: the hypothalamic-pituitary-adrenal axis coordinates hormonal responses through corticotropin-releasing hormone, adrenocorticotropic hormone, and cortisol to mobilize metabolic resources; the autonomic nervous system releases catecholamines including epinephrine and norepinephrine to drive immediate cardiovascular and respiratory adjustments; and the immune system responds to stress hormones by producing pro-inflammatory cytokines such as interleukin-1, interleukin-6, and tumor necrosis factor-alpha. While acute stress activation provides survival advantage, chronic dysregulation produces widespread pathology: sustained cortisol elevation contributes to visceral obesity, insulin resistance, bone demineralization, gastric pathology, cognitive impairment, and hippocampal atrophy, whereas prolonged catecholamine signaling fosters hypertension, atherosclerosis, and inflammatory vascular disease. Chronic inflammatory states precipitate autoimmune dysfunction, malignant progression, and physical frailty. Early life adversity emerges as a critical determinant of stress system dysfunction, with prenatal maternal stress and childhood trauma producing lasting alterations in brain development, emotional regulation, and immune function that increase lifetime risk for cardiovascular, metabolic, psychiatric, and autoimmune disease. Stress acceleration of cellular aging occurs through telomere shortening and oxidative damage mechanisms. The chapter synthesizes evidence for adaptive interventions including exercise, which modulates neurotransmitter systems and reduces inflammatory markers, and mindfulness-based therapies, which downregulate cortisol production and amygdala reactivity to improve emotional regulation and reduce symptom burden in chronic pain, depression, anxiety, and post-traumatic conditions. Coping effectiveness depends on harnessing resilience factors and social support while avoiding maladaptive behaviors that amplify disease risk.