Stress

Hans Selye (1956) defined stress as the nonspecific response of the body to any demand and described the General Adaptation Syndrome (GAS) in three phases: alarm (activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis), resistance (the organism attempts to adapt while maintaining elevated activation), and exhaustion (resources are depleted, opening the door to illness). Selye distinguished between eustress (positive stress that motivates and activates) and distress (negative stress that overwhelms and damages).

Lazarus and Folkman (1984) proposed the transactional model of stress, which transformed understanding of the phenomenon. According to this model, stress resides neither in the stimulus nor in the response, but in the relationship between the person and the environment. Cognitive appraisal is central: primary appraisal determines whether the situation is threatening, and secondary appraisal evaluates available resources for coping. Coping can be problem-focused (acting to modify the situation) or emotion-focused (regulating the emotional response when the situation cannot be changed).

McEwen (1998) introduced the concept of allostatic load to describe the cumulative wear on the organism when stress systems are repeatedly activated or fail to shut down adequately. Chronic stress affects virtually every body system: it increases cardiovascular risk, suppresses immune function, disrupts glucose regulation, impairs memory and executive functions (hippocampal and prefrontal damage), and contributes to the development of depression, anxiety, and somatoform disorders.

Resilience to stress depends on multiple factors: social support, sense of personal control, cognitive flexibility, healthy lifestyle habits, and meaning or life purpose. Evidence-based interventions include mindfulness (which reduces stress reactivity), cognitive restructuring (which modifies threatening appraisals), regular physical exercise (which regulates the HPA axis), and relaxation techniques. The goal is not to eliminate stress — a certain level of activation is necessary for performance — but to develop coping resources that enable healthy adaptation.