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Normal human metabolism produces heat at a basal metabolic rate of around 80 watts. [1] During a bicycle race, an elite cyclist can produce around 440 watts of mechanical power over an hour and track cyclists in short bursts over 2500 watts; modern racing bicycles have greater than 95% mechanical efficiency. An adult of good fitness is more ...
The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg−1 · °C−1 for tooth (enamel) to 4.2 kJ · kg−1 · °C−1 for eye (sclera).
As in other mammals, human thermoregulation is an important aspect of homeostasis. In thermoregulation, body heat is generated mostly in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. [1] Humans have been able to adapt to a great diversity of climates, including hot humid and hot arid.
Normal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is 36.8 ± 0.5 °C (98.2 ± 0.9 °F). [ 12 ]
Conversely, we are normally in surroundings that are considerably cooler than the body's core temperature of 37 °C (98.6 °F) creating a gradient for thermal energy flow from the core to the surroundings. Therefore, the body must ensure it can also minimize the loss of heat to around 100 watts, if it is to maintain core temperature.
For an overall efficiency of 20%, one watt of mechanical power is equivalent to 18 kJ/h (4.3 kcal/h). For example, a manufacturer of rowing equipment shows calories released from "burning" food as four times the actual mechanical work, plus 1,300 kJ (300 kcal) per hour, [16] which amounts to about 20% efficiency at 250 watts of mechanical output.
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Heat capacity, c p: 111.46 J/(mol K) [5] Liquid properties Std enthalpy change of formation, Δ f H o liquid: −277.38 kJ/mol Standard molar entropy, S o liquid: 159.9 J/(mol K) Enthalpy of combustion, Δ c H o: −1370.7 kJ/mol Heat capacity, c p: 112.4 J/(mol K) Gas properties Std enthalpy change of formation, Δ f H o gas: −235.3 kJ/mol ...