Decoding Stress: The Universal Language of Entropy Production

Abstract

The accurate quantification of stress remains a formidable challenge in the realm of physiological research, largely owing to the intricate nature of the stress response and its potential overlap with other physiological processes. In this vein, our research introduces a novel metric: the stress entropic load (SEL), grounded in thermodynamic principles. SEL is mathematically construed as a time-dependent function, articulated through various heat and temperature alterations, as well as changes in respiratory gas exchanges. This measure is posited as a predictive tool for stress and metabolic alterations in homeothermic organisms, including humans. Our empirical exploration involved 12 healthy male volunteers, structured in a dual-phase experimental design. The initial phase focused on achieving a resting metabolic rate (RMR), guided by specific criteria encompassing oxygen uptake, carbon dioxide release, and respiratory quotient. In instances where RMR benchmarks were not met within a 40-minute window, the study progressed, presuming RMR attainment. The collected data from this segment were pivotal in calculating the body's entropy production at rest. The subsequent phase entailed participants engaging in tasks via the WinSCAT software, signifying the onset of the stress phase. Here, entropy production was scrutinized to gauge stress levels. Crucially, SEL was ascertained by contrasting entropy production during the RMR phase (serving as a baseline) against that recorded throughout the experiment's entirety. Our findings indicate that SEL, as an indicator of specific entropy production, emerges as a viable marker of stress induced by prolonged mental effort. Notably, extended interaction with WinSCAT software markedly augmented SEL rates. The progression of SEL over time offered insights into when participants commenced stress-inducing tasks, underscoring its viability as a biological marker for mental exertion. Intriguingly, such stress did not manifest in conventional stress indicators like blood pressure or heart rate, though it did affect oxygen and carbon dioxide production. While these results lend credence to the utility of SEL as a stress marker, they are preliminary in nature, illuminating the prospective significance of SEL in the realms of stress measurement and physiological research. The project was funded by MUNI/G/1249/2021 grant by the Masaryk University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.