Stress: the general adaptation syndrome and allostatic load
- Concept
Stress is the body's and mind's response to a demand. Short bursts help us cope; when it never switches off, it wears the body down.
What it is
Stress is the whole response of a person to a demand that is judged to exceed what can be handled easily. Hans Selye described a fixed three-stage sequence, the general adaptation syndrome, seen with almost any prolonged stressor. Bruce McEwen later reframed it: the body keeps stability through change (allostasis), and the cost of repeated or prolonged activation is allostatic load. The hormones and nerves involved are on the physiology page; this page is about the model and its clinical meaning.
Key facts
- Four patterns of allostatic load: too many stress hits, failure to adapt to a repeated stressor, a response that does not switch off, and an inadequate response that lets other systems overshoot.
- Chronic stress is linked to hypertension, coronary disease, poorer immune responses, slower wound healing and sleep disruption.
- The stress response follows an inverted-U curve with performance: too little arousal and too much both impair it.
- Selye's model is non-specific (any stressor, the same response); modern models add appraisal and individual differences.
Selye's three stages and what they look like in a patient
| Stage | What happens | Clinical picture |
|---|---|---|
| Alarm | Fast sympathetic and hormonal mobilization to face the threat | Tachycardia, sweating, alertness right after an accident or bad news |
| Resistance | The body adapts and stays activated at a lower, sustained level | Weeks of caring for a sick relative: functioning, but tense and sleeping poorly |
| Exhaustion | Reserves run out and adaptation fails | Fatigue, infections, flare of chronic illness, low mood |
Clinical notes
- Acute emotional stress can trigger stress cardiomyopathy (takotsubo), a reversible left-ventricular dysfunction that mimics an infarction.
- Asking about stressors and sleep belongs in the history of hypertension, chest pain without obstruction and recurrent infections.
Test yourself
Think of the answer, then tap the question to see it.
What are the three stages of Selye's general adaptation syndrome?
Alarm, resistance and exhaustion.
What is allostatic load?
The cumulative wear on the body from repeated, prolonged or poorly ended stress responses: the price of adapting.
Which stage of the general adaptation syndrome corresponds to Cannon's fight-or-flight response?
The alarm stage.
What is the difference between eustress and distress?
Eustress is a level of stress that helps performance; distress is excessive stress that impairs performance and health.
Elsewhere in DurgiPedia
- The endocrine stress response
- The HPA axis and its circadian rhythm
- The adrenal medulla and catecholamines
- The limbic system, emotion and reward
Connections
Educational content on behavior and the clinical relationship; not a diagnostic or treatment guide and no substitute for assessment by a health professional. If you or someone near you is at risk, seek help now from an emergency service or a mental-health helpline.
Sources: Stress and the “extended” autonomic system (Autonomic Neuroscience, via PubMed Central (US National Library of Medicine), 2021); Critical Biological Pathways for Chronic Psychosocial Stress and Research Opportunities to Advance the Consideration of Stress in Chemical Risk Assessment (American Journal of Public Health, via PubMed Central (US National Library of Medicine), 2011).
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Representative model, for educational purposes only.