Allostatic Load

Definition

Allostatic load is the cumulative biological burden that builds up when the body's stress-response systems are repeatedly or chronically activated. It reflects the long-term wear and tear associated with maintaining stability through change, including changes in systems such as the nervous system, endocrine system, immune system, metabolism, and cardiovascular regulation. [1] [2] [3]

Why It Matters in Ageing Research

Allostatic load matters because ageing is influenced not only by molecular damage and genetics, but also by long-term exposure to physical, psychological, social, and environmental stressors. Researchers use allostatic load models to study how cumulative stress relates to inflammation, metabolic dysfunction, cardiovascular risk, frailty, cognitive decline, mortality, and health inequalities across the life course. [3] [4] [5]

Common Confusion

• Allostatic load is not the same as feeling stressed; it refers to measurable biological burden across multiple systems.
• Short-term stress responses can be adaptive, while chronic or repeated activation can become harmful.
• Allostatic load is usually measured with a panel of biomarkers rather than a single definitive test.

Related Reading

• What Is a Biomarker of Ageing?
• Biomarker
• Frailty
• Inflammaging

References

1. McEwen, B. S., & Stellar, E. (1993). Stress and the individual: Mechanisms leading to disease. https://pubmed.ncbi.nlm.nih.gov/8379800/
2. McEwen, B. S. (1998). Protective and damaging effects of stress mediators. https://pubmed.ncbi.nlm.nih.gov/9634234/
3. McEwen, B. S., & Wingfield, J. C. (2003). The concept of allostasis in biology and biomedicine. https://pubmed.ncbi.nlm.nih.gov/12749634/
4. Seeman, T. E., et al. (2001). Allostatic load as a marker of cumulative biological risk. https://pubmed.ncbi.nlm.nih.gov/11730249/
5. Juster, R. P., McEwen, B. S., & Lupien, S. J. (2010). Allostatic load biomarkers of chronic stress and impact on health and cognition. https://pubmed.ncbi.nlm.nih.gov/19822172/