Allostatic load is the cumulative wear and tear on the body from chronic or repeated stress exposure. The concept was introduced by Bruce McEwen and Eliot Stellar in 1993. ## Types **Type 1**: energy demand exceeds supply, forcing survival mode (starvation, hibernation, critical illness); thyroid hormone drops. **Type 2**: sufficient or excess energy but ongoing social conflict or dysfunction, common in human society; triggers no escape response; thyroid hormone rises instead of falling. ## Health Impacts - Cognitive and physical decline in older adults - Cardiovascular disease and high blood pressure - Mental health conditions: depression, anxiety, schizophrenia - Changes in brain structure and volume ## Measurement - **Biomarkers**: cortisol, heart rate variability, glucose, lipid profiles, inflammatory markers - **Clinical assessment**: symptoms and signs of stress-related wear ## Risk Factors - Work-related stress and burnout - Poor job quality - Insufficient recovery from stress - Effort-reward imbalance - Chronic exposure to stressors without adequate adaptation When environmental challenges exceed an individual's coping ability, allostatic overload occurs: the point where chronic stress starts producing measurable disease risk. ## Related - [[Social Connection Outperforms Status as Stress Buffer]] — Sapolsky's baboon research is a real-world case of Type 2 allostatic load: social conflict/dysfunction (status competition) drives chronic cortisol even with no physical threat and no escape response, while genuine affiliation reduces it - [[Dopamine Dysregulation in High Performers]] — adds neurochemical specificity to this note's general wear-and-tear concept: dopamine-receptor desensitization from constant stimulation is a measurable Type 2 allostatic mechanism specific to high performers, not a subjective feeling ## Sources - Concept origin, types, thyroid distinction: [Wikipedia — Allostatic load](https://en.wikipedia.org/wiki/Allostatic_load) - Health impacts, biomarkers, clinical assessment: [Karger — Allostatic Load and Its Impact on Health](https://karger.com/pps/article/90/1/11/294736/Allostatic-Load-and-Its-Impact-on-Health-A) - Overload threshold: [Nature — McEwen, Protective and Damaging Effects of Stress Mediators](https://www.nature.com/articles/1395453) - Mental health conditions: [Taylor & Francis — Stress Neuroendocrinology and Allostatic Load](https://www.tandfonline.com/doi/full/10.1080/10253890.2020.1813711) - Additional: [PubMed](https://pubmed.ncbi.nlm.nih.gov/32799204/) · [Newport Healthcare](https://www.newporthealthcare.com/resources/industry-articles/reduce-your-allostatic-load/) · [PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC10716872/) · [Verywell Mind](https://www.verywellmind.com/what-is-allostatic-load-5680283)