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This increases heat production as respiration is an exothermic reaction in muscle cells. Shivering is more effective than exercise at producing heat because the animal (includes humans) remains still. This means that less heat is lost to the environment through convection. There are two types of shivering: low-intensity and high-intensity.
Also, humans had physiological mechanisms that reduced the rate of metabolism and that modified the sensitivity of sweat glands to provide an adequate amount for cooldown without the individual becoming dehydrated. [17] [20] There are two types of heat the body is adapted to, humid heat and dry heat, but the body adapts to both in similar ways.
The statement of Newton's law used in the heat transfer literature puts into mathematics the idea that the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings. For a temperature-independent heat transfer coefficient, the statement is:
The process of heat transfer from one place to another place without the movement of particles is called conduction, such as when placing a hand on a cold glass of water—heat is conducted from the warm skin to the cold glass, but if the hand is held a few inches from the glass, little conduction would occur since air is a poor conductor of heat.
Biological thermodynamics (Thermodynamics of biological systems) is a science that explains the nature and general laws of thermodynamic processes occurring in living organisms as nonequilibrium thermodynamic systems that convert the energy of the Sun and food into other types of energy.
Energy intake is measured by the amount of calories consumed from food and fluids. [1] Energy intake is modulated by hunger, which is primarily regulated by the hypothalamus, [1] and choice, which is determined by the sets of brain structures that are responsible for stimulus control (i.e., operant conditioning and classical conditioning) and cognitive control of eating behavior.
Endothermic organisms known as homeotherms maintain internal temperatures with minimal metabolic regulation within a range of ambient temperatures called the thermal neutral zone (TNZ). Within the TNZ the basal rate of heat production is equal to the rate of heat loss to the environment. Homeothermic organisms adjust to the temperatures within ...
The term Lewis reaction is used too, named after Thomas Lewis, who first described the effect in 1930. [1] Vasoconstriction occurs first to reduce heat loss, but also results in strong cooling of the extremities. Approximately five to ten minutes after the start of cold exposure, the blood vessels in the extremities will suddenly vasodilate.