Furthermore, the work done by Garby and Larsen and Jou and Llebot addresses mass, energy, and entropy balance of open living systems but not Maxwell relations. The seminal work done in the areas of biological thermodynamics by Morowitz does not show any application of Maxwell relations to model human physiology. Aoki examined human thermoregulation by measuring entropy flow and production in basal and exercising conditions but did not utilize Maxwell relations to include other physiological responses. It has been hypothesized by Bridgman that the laws of thermodynamics are intrinsic to nature and life and are thus well positioned to characterize the physiological behavior of living systems. IntroductionĮarlier work done by several researchers has established the fact that human life processes are indeed thermodynamic in nature and hence thermodynamic laws can be used to model human physiology. The results demonstrate that entropy change provides a valuable composite measure of individual physiological response to various stressors that could be valuable in the areas of medical research, diagnosis, and clinical practice.
ENTROPY CHANGE SKIN
Two types of entropy change were computed: (a) entropy change ( ) due to blood pressure, heart rate, and skin temperature and (b) entropy change ( ) due to electromyogram, electrodermal response, and skin temperature. The methodology included data collection during a relaxation period of eighteen minutes followed by a sixty-minute cognitive task. The multiple time-series physiological data were collected from eight subjects in an experimental pilot study conducted at the Human Engineering Laboratory of NASA Langley Research Center. The physiological measures included blood pressure (BP), heart rate (HR), skin temperature (ST), electromyogram (EMG), and electrodermal response (EDR). The paper presents a novel approach involving the use of Maxwell relations to combine multiple physiological measures to provide a measure of entropy change.