In lecture 27 we looked at a similar energy balance equation from the point of view of nutrition and metabolism. The equation above lumps the heat energy from work, digestion, etc. into the single variable of metabolic energy and focuses on the four variables R,C,K,E representing the various energy exchanges with the environment. The human body is a dynamic system, in a dynamic environment, yet the most important functions tend to be stable. The phenomenon of self-regulating stability in a dynamic environment is referred to as homeostasis. A variety of parameters are regulated in the body, including blood sugar levels and levels of various chemical enzymes and hormones.
Temperature is one of the most closely regulated of body parameters.
Relatively small variations in core temperature can be life threatening. For instance, a high fever represents an increase of just a few degrees Celsius over the normal core temperature. The regulation of body temperature occurs in response to a changing thermal environment. There are a number of key parameters in the environment which influence the amount of thermal stress that the body experiences. People differ in their response to thermal stress.