Recovery physiology: a testable systems framework for preserving the capacity to function

Living systems must restore function after perturbation while operating under finite energetic, structural, regulatory, and environmental constraints. This Hypothesis and Theory article proposes Recovery Physiology as a testable framework for studying that problem. Recovery is defined narrowly as the time-dependent response following a prospectively specified perturbation that measurably displaces one or more prespecified functional variables from a relevant reference state. Recovery Capacity (RC) is defined separately as a hypothetical latent, context-dependent property that may influence the magnitude, rate, completeness, coordination, and cost of that response; favorable outcomes are not evidence of high RC by definition. Three candidate domains—bioenergetic capacity, biological information integrity, and systems coordination—are proposed as a parsimonious but revisable architecture. The framework makes three separable claims: recovery phenotypes may contain reliable challenge-specific latent structure and possibly a higher-order cross-challenge factor; the proposed domain architecture may explain recovery beyond simpler alternatives; and dynamic trajectories may add prognostic information beyond baseline state and established constructs. Each claim is paired with competing models and falsification criteria. A standardized exercise protocol illustrates how reliability, construct validity, incremental predictive validity, cross-challenge generalization, and intervention responsiveness could be tested. Recovery Physiology is not presented as a new discipline or clinical system. Its value depends on whether prespecified recovery measures outperform parsimonious models based on age, baseline function, disease burden, frailty, physiological reserve, intrinsic capacity, allostatic load, and established resilience measures.