Loss of thermodynamic efficiency of various organs and functions of Drosophila melanogaster during aging.

Aging is a universal phenomenon characterized by a progressive decline in physiological function. In this study, we applied a rigorous physical theory based on irreversible thermodynamics to analyze experimental data from Drosophila melanogaster. We establish a unifying principle: the functional thermodynamic efficiency loss parameter per cycle (α). This parameter is proportional to the specific entropy produced in a functional cycle relative to the total entropy produced until failure. By analyzing 61 values across various organs and functions, we identified a "quantized" behavior in functional aging. Furthermore, we determined the maximum energy dissipated per unit mass (μlmg) throughout the lifespan. These findings suggest a fundamental architecture in biological energy allocation. This thermodynamic approach offers a novel, quantitative method for evaluating aging and testing interventions, providing a solid alternative to traditional demographic biomarkers.