title: 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.
authors: a Institute of Sport and Movement Science , University of Stuttgart , Stuttgart , Germany .
authors: Stefan
authors: S
authors: Hochstein
authors: b Institute of Aerospace Thermodynamics , University of Stuttgart , Stuttgart , Germany .
authors: Philipp
authors: P
authors: Rauschenberger
authors: b Institute of Aerospace Thermodynamics , University of Stuttgart , Stuttgart , Germany .
authors: Bernhard
authors: B
authors: Weigand
authors: a Institute of Sport and Movement Science , University of Stuttgart , Stuttgart , Germany .
authors: Tobias
authors: T
authors: Siebert
authors: a Institute of Sport and Movement Science , University of Stuttgart , Stuttgart , Germany .
authors: Syn
authors: S
authors: Schmitt
authors: a Institute of Sport and Movement Science , University of Stuttgart , Stuttgart , Germany .
authors: Wolfgang
authors: W
authors: Schlicht
authors: c Institute of Thermomechanics , ASCR Prague , Prague , Czech Republic .
authors: Světlana
authors: S
authors: Převorovská
authors: d Department of Polymer Technologies of New Technologies Research Centre , University of West Bohemia , Plzen , Czech Republic .
authors: František
authors: F
authors: Maršík
mesh_terms: D019277:Entropy; D016552:Ergometry; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D018594:Human Body; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: Physical activity; activity assessment; cardiovascular model; entropy