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The specific heat of the human body calculated from the measured values of individual tissues is 2.98 kJ · kg−1 · °C−1. This is 17% lower than the earlier wider used one based on non measured values of 3.47 kJ · kg−1· °C−1.
Human power is the rate of work or energy that is produced from the human body. It can also refer to the power (rate of work per time) of a human. Power comes primarily from muscles , but body heat is also used to do work like warming shelters , food, or other humans.
This creates a limit to the amount of heat energy that can do work in a cyclic process, a limit called the available energy. Mechanical and other forms of energy can be transformed in the other direction into thermal energy without such limitations. [14] The total energy of a system can be calculated by adding up all forms of energy in the system.
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.
In chemistry, heat amounts are often measured in calories. Confusingly, two units with that name, denoted "cal" or "Cal", have been commonly used to measure amounts of heat: The "small calorie" (or "gram-calorie", "cal") is exactly 4.184 J. It was originally defined so that the heat capacity of 1 gram of liquid water would be 1 cal/°C.
The amount of energy required to warm one gram of air-free water from 3.5 to 4.5 °C at standard atmospheric pressure. [b] 15 °C calorie: cal 15: ≈ 4.1855 J ≈ 0.003 9671 BTU ≈ 1.1626 × 10 −6 kW⋅h ≈ 2.6124 × 10 19 eV The amount of energy required to warm one gram of air-free water from 14.5 to 15.5 °C at standard atmospheric ...
Origins of heat and cold adaptations can be explained by climatic adaptation. [16] [17] Ambient air temperature affects how much energy investment the human body must make. The temperature that requires the least amount of energy investment is 21 °C (70 °F). [5] [disputed – discuss] The body controls its temperature through the hypothalamus.
The principles of heat transfer in engineering systems can be applied to the human body to determine how the body transfers heat. Heat is produced in the body by the continuous metabolism of nutrients which provides energy for the systems of the body. [ 43 ]