ABSTRACT
In humans, normal body temperature is approximately 37°C (98.6°F ). This value refers to the internal or core temperature, which is commonly measured orally and rectally. On the other hand, shell temperature, which represents the temperature of the skin and the tissues directly under it, varies considerably depending upon the surrounding environmental temperature. At rest, rectal temperature is normally 0.5-1°F higher than oral temperature; however, it was reported that following a road race, rectal temperature was 5.5°F higher than oral temperature, suggesting that an oral reading may not be an accurate reflection of the true body temperature. The body is able to maintain its core temperature by controlling the rate of heat production and the rate of heat loss. As shown in Figure 14.1, body temperature reflects a careful balance between heat production and heat loss. When out of balance, the body either gains or loses heat. The temperature control center, which is located in the hypothalamus, works like a thermostat; it can initiate an increase in heat production when body temperature falls and an increase in heat loss when body temperature rises.
