Assessment of physical activity of the human body considering the thermodynamic system

Abstract

Correctly dosed physical activity is the basis of a vital and healthy life, but the measurement of physical activity is certainly rather empirical resulting in limited individual and custom activity recommendations. Certainly, very accurate three-dimensional models of the cardiovascular system exist, however, requiring the numeric solution of the Navier-Stokes equations of the flow in blood vessels. These models are suitable for the research of cardiac diseases, but computationally very expensive. Direct measurements are expensive and often not applicable outside laboratories. This paper offers a new approach to assess physical activity using thermodynamical systems and its leading quantity of entropy production which is a compromise between computation time and precise prediction of pressure, volume, and flow variables in blood vessels. Based on a simplified (one-dimensional) model of the cardiovascular system of the human body, we develop and evaluate a setup calculating entropy production of the heart to determine the intensity of human physical activity in a more precise way than previous parameters, e.g. frequently used energy considerations. The knowledge resulting from the precise real-time physical activity provides the basis for an intelligent human-technology interaction allowing to steadily adjust the degree of physical activity according to the actual individual performance level and thus to improve training and activity recommendations.

Energy Expenditure of Dynamic Submaximal Human Plantarflexion Movements: Model Prediction and Validation by in-vivo Magnetic Resonance Spectroscopy

“…Combining these methods will allow to investigate energy consumption in dynamic movements in much more realistic detail than before (Umberger and Rubenson, 2011 ). In the future, muscular energy expenditure models may be combined with the energy consumption of the cardio-vascular system to obtain a better model for whole body energetics (Hochstein et al, 2016 ).…”

Dependence of Temperature Rise on the Position of Catheters and Implants Power Sources Due to the Heat Transfer into the Blood Flow

“…The human body has an internal mechanism for controlling temperature (cooling and heating) to return any abnormal temperature changes to the normal range [1]. This mechanism is mainly adapted for controlling external factors such as environment temperature variation [2][3][4][5][6]. Any changes in the local temperature of the body can be detected by the temperature control mechanism to maintain the safety of the body, while if it exceeds the normal range, it can damage the body tissues [7][8][9][10][11][12].…”

Energy Homeostasis and the Law of Thermodynamics

“…Through the subject of thermodynamics, nature, characteristics, and forms of energy can be understood. Also, through the subject, the working principles and mechanisms of bodies that utilise energy can be understood [1]. The human body is a typical example, it requires energy for the perpetuation of biological functions and gains energy primarily through food intake.…”