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Function Estimation
Published in M. Necati Özisik, Helcio R. B. Orlande, Inverse Heat Transfer, 2021
M. Necati Özisik, Helcio R. B. Orlande
Thermogenesis results from the cellular metabolism and has a fundamental role for body thermoregulation in endothermic species. The motivation for the inverse problem presented in this section is the analysis of the kidneys’ contribution for thermoregulation [144]. The MCMC method is applied for the solution of the inverse problem, which presents inherent difficulties associated with low sensitivity of the parameters of main interest that represent the transient heat source term, and strong correlation of the remaining model parameters. Such difficulties were dealt with by using the version of the Metropolis-Hastings algorithm that samples the parameters in blocks, presented in Note 1 of Chapter 4. Simulated temperature measurements were used for the inverse problem solution and the convergence of the Markov chains was verified with the techniques presented in Section 4.6.
Human Thermal Comfort
Published in Ken Parsons, Human Thermal Comfort, 2019
Blood absorbs the metabolic heat production due to activity and transports it around the body to the skin, which is the main surface for heat exchange. When a person is too hot, blood flows to the skin surface, raising its temperature and hence increasing potential loss of heat by convection from the body to the environment. Sweating wets the surface of the skin and increases greatly the potential for heat loss by evaporation. Withdrawal of the blood from the skin when the body is too cold reduces skin temperature and decreases the potential for heat loss by convection. Non-shivering thermogenesis and shivering increase metabolic heat. All physiological responses are an attempt to maintain internal body temperature at around 37°C. The magnitude of response is related to the thermal condition of the body. It is reasonable to assume that the strength of the response is related to a combination of internal body and skin temperatures, involving both temperature and rate of change of temperature, and the difference between set or desired temperatures and actual temperatures.
Human Thermoregulation System and Comfort
Published in Guowen Song, Faming Wang, Firefighters’ Clothing and Equipment, 2018
Metabolic rate (M, in W) is the rate of metabolic energy expenditure of the human body to maintain basic functions and perform activities by consuming energy sources inside the human body. Thermogenesis is the term used to describe internal heat production in this process. There are two types of thermogenesis: shivering thermogenesis and nonshivering thermogenesis. Metabolic rate is always positive. At rest, there is a basal metabolic rate. During work and exercise, a large amount of energy expenditure is mainly caused by the activities of skeletal muscles. A large fraction of the energy consumed is converted to heat. A small fraction goes to external work (W, in W), depending on the type of activities. The excess heat should be dissipated from the body to the environment. Otherwise, heat will be stored (S, in W) in the human body leading to increased core and skin temperatures. There are four avenues of heat exchange between the human body and external environments: conduction (K, in W), convection (C, in W), radiation (R, in W), and evaporation (E, in W). Depending on environmental conditions, the human body can lose or gain heat to/from the external environment. In hot environments, for example, with strong radiant heat from sun and fire, the body may gain heat. Respiration (Res) is another way of heat exchange. Therefore, the heat balance equation is expressed as S=(M−W)−(K+C+R+E+Res)
Plasma irisin is increased following 12 weeks of Nordic walking and associates with glucose homoeostasis in overweight/obese men with impaired glucose regulation
Published in European Journal of Sport Science, 2019
Ayhan Korkmaz, Mika Venojärvi, Niko Wasenius, Sirpa Manderoos, Keith C. Deruisseau, Eva-Karin Gidlund, Olli J. Heinonen, Harri Lindholm, Sirkka Aunola, Johan G. Eriksson, Mustafa Atalay
Irisin may enhance systemic metabolism by increasing energy expenditure and UCP-1 (uncoupling protein-1) expression in adipose tissue (Bostrom et al., 2012; Kelly, 2012; Perakakis et al., 2017). Increased thermogenesis augments energy expenditure that could aid in the prevention of obesity and maintenance of normal glucose metabolism (Bostrom et al., 2012; Perakakis et al., 2017). Irisin may play a role in promoting insulin sensitivity that could be an important mediator of the counteracting effect of physical exercise on obesity related glucose disturbances.