Allostatic load (AL) is a term used to describe the cumulative physiological wear and tear that results from repeated efforts to adapt to stressors over time. Unlike other psychobiological models of stress that focus on a single outcome variable (e.g., cortisol) or physiological system (e.g., the hypothalamic-pituitary-adrenal –HPA- axis), the AL model emphasizes multi-system dysregulation.
By combining multiple biological risk factors into a composite score, risk for a variety of stress-exacerbated diseases can be assessed in healthy individuals prior to signs and symptoms of clinical disease. Also, use of a composite AL may allow for quantification of stress burden across multiple (co morbid) mental health diagnoses, thereby reducing the problems associated with overlapping diagnostic classifications, particularly among mood and anxiety disorders.
A composite AL score reflecting cardiovascular activity, atherosclerosis development, HPA axis functioning, glucose metabolism and sympathetic nervous system (SNS) activation has been shown to increase with age and to predict long-term morbidity and mortality among large elderly samples. In addition, lower AL scores have been associated with positive social experiences in late middle-age (58+) and older adults.
For my fellow nerd-types. 🙂