PMC

Representative recording of body temperature (black line), metabolic rate (MR, grey line), total evaporative heat loss (total EHL, REHL + CEHL; pink line), respiratory evaporative heat loss (blue line), and cutaneous evaporative heat loss (red line) in one zebra finch measured at T_a = 40 °C. Black arrows indicate the time of wing drooping (color figure online)

Heat balance of a patient following the simulation. White parts represent the heat fluxes through the open back segment. Black parts represent the heat flows through the other body parts. Visible from left to right: evaporative heat loss (Q _e), radiative heat loss (Q _r), convective heat loss (Q _c), metabolic heat production (M), evaporative respiratory heat loss (E _rsp ) and dry respiratory heat loss (C _rsp ). The radiative heat gain of the open back segment is caused by the radiative heat flux of the surgery light. The convective heat gain comes from heat input of the forced-air heating blanket. In this specific case, the overall heat balance is positive, which means that the body is warming

Example of total quantities of energy exchanged and stored with the ingestion of cold (1.5°C) or body temperature-controlled (38°C) water during exercise under neutral environmental conditions. ΔH_b, change in body heat storage; H_fluid, energy exchanged between body tissues and ingested water; H_{evap_skin}, evaporative heat loss; H_res, respiratory heat loss; H_dry__skin, dry heat loss; H_prod, metabolic heat produced. Negative values indicate heat loss (i.e., cooling). In this example, net body heat storage is slightly greater with the ingestion of cold fluid because of a corresponding attenuation in whole body evaporative heat loss.

Figure 2. Thermal network to describe heat balance in the thermoneutral zone. Tc: core temperature, T_s: mean skin temperature, T_a: ambient temperature, (1−α)M: metabolic rate corrected for respiratory heat loss, Q_r+c: combined radiative and convective heat loss, Ps: saturated vapor pressure at skin surface, P_a: vapor pressure of the air, Q_e: evaporative heat loss, h_c: convective heat loss coefficient, Fpcl: clothing evaporative permeability coefficient, I_body: body insulation, I_cl: clothing insulation, I_a: air insulation.