The Ontology of Health and Longevity: The Energy-Efficiency Dynamics of Constraint Steady States

Health and longevity are universal aspirations, yet their underlying principles remain fragmented across disciplines. This paper develops a unified framework within Energy-Efficiency Theory (EET). Starting from the three axioms, we propose that health is the maintenance efficiency of constraint steady states, and longevity is the temporal integral of this efficiency. The Health Index is defined as: H(t) = 0.7·(Ė_main/Ė_repair) + 0.3·(B_flex/B_0), where Ė_main is the maintenance energy rate, Ė_repair the repair energy demand, B the Ben-Shi parameter (conservation-expansion balance), B_flex the 7‑day range of B, and B_0 = 0.5. Healthy range: H ∈ [0.8, 1.0]; values above 1.0 indicate a transient super-healthy state (e.g., youth or effective interventions). Healthspan prolongation corresponds to maintaining Ė_main ≈ Ė_repair and flexible B. Four intervention strategies are mapped to the parameters of the Ben-Shi equation: (1) increase Ė_main (caloric restriction, exercise); (2) decrease Ė_repair (anti-inflammatories, senolytics); (3) optimize β (intermittent fasting, hormesis); (4) maintain B flexibility (cognitive training, social engagement). The framework distinguishes healthspan from lifespan, showing that interventions targeting Ė_main/Ė_repair extend healthspan more than lifespan alone. Three falsifiable predictions with statistical power validation are proposed. Together with our previous works on origin and replication, and the companion paper on aging and death, this work completes the EET life cycle: how life begins, how it continues, how it is maintained, and how it ends.