Population Allostatic Load: A Framework for Measuring Accumulated Adaptive Burden in Populations

Allostatic load is the cumulative physiological burden an organism carries when repeated demands are not fully recovered from. The concept is foundational in behavioral medicine and public health, but no parallel framework estimates accumulated adaptive burden at the scale of populations. This paper proposes Population Allostatic Load (PAL) as that extension. Its central proposition is that populations, like organisms, accumulate burden when the demands placed on them arrive faster than they can be recovered from, and that the decisive variable is not the size of any single shock but the population’s capacity to recover. The paper defines the construct, distinguishes it from stress, crisis, and vulnerability, introduces its three components (Compression, Collective Recovery Potential, and Reserve), and states the requirements a measurement model must meet to be testable. Operationalization follows in ATI-PALI-02. The shared vocabulary, accumulation equation, and methodological rules are defined in ATI-ARCH-01.