Allostatic load is the "wear and tear" on the body that accumulates from repeated or chronic stress. The term was introduced by Bruce McEwen and Eliot Stellar in 1993 to describe the physiological price of the constant mobilization of the adaptation systems.
At its core is the concept of allostasis — the ability to maintain stability through change (a faster pulse, a release of cortisol). This is useful in the short term, but when the stress response switches on too often or does not switch off in time, the load accumulates and begins to do harm.
How it is measured
Allostatic load is assessed not by a single test but by a composite index of biomarkers from several systems. Usually the stress hormones (cortisol, catecholamines, DHEA), blood pressure, and markers of inflammation (hs-CRP and other inflammatory markers) are taken into account.
Metabolic markers are added — HbA1c, lipids and HDL cholesterol, waist circumference. The more indicators that fall outside the "healthy" range, the higher the total load. In essence, this is an integrated portrait of how stress has left its imprint on the body.
What it threatens and what to do
A high allostatic load is associated with coronary heart disease and metabolic syndrome, decline in cognitive function (the hippocampus, prefrontal cortex and amygdala suffer) and increased all-cause mortality. Chronic stress also increases oxidative stress, accelerating biological aging.
The load can be lowered by managing chronic stress, getting enough sleep, regular physical activity and social support. Subjective stress levels can be tracked with the perceived-stress scale, and the cumulative "wear" with biomarker and biological-age calculators.
Calculate using this marker
Calculators where Allostatic load is used directly:
Frequently asked questions
How does allostatic load differ from "stress"?
Stress is a reaction here and now, while allostatic load is the accumulated result of many such reactions, imprinted in biomarkers (blood pressure, cortisol, inflammation, blood sugar). It is a measure of the long-term price of chronic stress.
Can allostatic load be reduced?
Yes. Regular sleep, physical activity, stress-management techniques and social support all help. They normalize blood pressure, inflammation and metabolism, and thereby reduce the cumulative wear on the body's systems.
Related terms
Sources
- Wikipedia — Allostatic load
- McEwen BS — Protective and damaging effects of stress mediators (Dialogues Clin Neurosci, 2006)