1 · Selye's General Adaptation Syndrome
In this model, the body answers any stressor the same way: alarm first, then resistance, and exhaustion only when demand outlasts its capacity to adapt.Hans Selye (1936) proposed the body responds to any stressor (cold, infection, emotional stress, exercise) in the same pattern, in three phases:1. Alarm: fight-or-flight — axis activation, epinephrine/cortisol surge
2. Resistance: body adapts and compensates — cortisol stays elevated but you 'cope'
3. Exhaustion: sustained demand exceeds adaptive capacity — the acquired resistance is lost, with immunosuppression and tissue damage; not the adrenals running out of cortisol. Modern chronic stress is HPA dysregulation (often high or a flattened morning peak, sometimes low)
Key insight: stress itself doesn't make you sick; your response to it does. The same workload leaves some people thriving and others burned out.