Thermal pleasantness and temperature regulation in man.

The temperature regulation system of man is complex and has not yet been fully understood. The "black box" is the nature of the set point which the system is known to defend. The set point is in fact a rhythmic function of time of day. Temperature-regulatory behaviour, more than autonomous response, has recently been confirmed as the dominant, effective and more sensitive control response tending to maintain body temperature close to the set point. It is possible to estimate the set point by a procedure involving a behavioural indicator, namely thermal pleasantness sensation. A number of examples are discussed in which the set point was determined by the aid of thermal alliesthesial response (i.e., change of thermal pleasantness sensation for the same stimulus according to the internal thermal state of the subject). The quantification of the set point is shown to be relevant for medical research and practice.