Relationship between metabolic rate and blood perfusion under Fanger thermal comfort conditions

• Published in: Journal of thermal biology Vol. 80; pp. 94 - 105
• Main Authors: Marn, Jure, Chung, Mo, Iljaž, Jurij
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2019; Elsevier BV
• Subjects: Adiabatic; Adipose Tissue - blood supply; Adipose Tissue - physiology; Algorithms; Asymptotic solution; Blood; Blood perfusion; Body Temperature; Conduction; Energy balance; Energy Metabolism; Environmental conditions; environmental factors; equations; Fanger thermal comfort; Heat; Heat transfer; Humans; Metabolic rate; Metabolism; Models, Biological; Muscle, Skeletal - blood supply; Muscle, Skeletal - physiology; muscles; Pennes bioheat equation; Perfusion; Regional Blood Flow; Skin; skin temperature; Temperature; Temperature distribution; Temperature effects; Thermosensing; Temperature distribution; Pennes bioheat equation; Blood perfusion; Asymptotic solution; Fanger thermal comfort
• ISSN: 0306-4565; 1879-0992
• DOI: 10.1016/j.jtherbio.2019.01.002

The one-dimensional steady Pennes (bioheat) equation was applied to analyze heat conduction inside a combined layer of human muscle and fat, under Fanger thermal comfort conditions. The bioheat equation was solved subject to two boundary conditions at the skin surface: a prescribed skin temperature satisfying the Fanger comfort criterion, and a prescribed heat flux obtained from the overall energy balance for the system. In addition to a fixed body core temperature, an adiabatic condition was imposed as an auxiliary condition at the core of the body, and a pair of equations were derived, relating the blood perfusion and the volumetric heat generation rate for a given activity level and environmental conditions. By solving the two equations, we determined the functional dependence of blood perfusion and metabolic heat generation on the human activity level. For convenience, we presented simple explicit expressions for the key relations, with the aid of asymptotic analyses. Additional results include the temperature distribution inside the muscle layer, and the effects of muscle and fat layer thickness on the heat transfer processes. •Steady heat conduction problem under Fanger thermal comfort condition is solved.•One-dimensional steady-state Pennes bioheat equation is applied.•Relationship between metabolic rate and blood perfusion determined.•Temperature distribution in the muscle layer is obtained.•Explicit expressions for key relations are determined by asymptotic analysis.