Thermoregulatory behaviour in response to switching thermal environments – a pilot experiment prior to a mild warm acclimation study

The indoor climate is an important factor with respect to human health and comfort since we spend most of our time, no matter if awake or asleep, in the built environment. Building occupants influence their thermal environments to maximize thermal comfort by inducing thermoregulatory behaviour. In the last decades, overheating of cities and buildings became an important issue. However, the effect of a mild hot environment on human thermoregulatory behaviour remains unclear.  To study the effects of a mild warm environment we propose a mild warm acclimation study. Part of this study is to investigate the effect of an alternated thermal environment on thermo-physiology and thermoregulatory behaviour before and after acclimation. In this paper we address the first results of a pilot study. The pilot aimed to elucidate interactions between human thermo-physiology, thermoregulatory behaviour and thermal comfort in response to altering thermal environments, the so-called SWITCH protocol. The pilot measurements demonstrate that thermoregulatory behaviour is initiated upon decreasing levels of thermal sensation and thermal comfort. Furthermore, we found indications for distinct thermoregulatory mechanisms in the three tested subjects, based on behaviour and skin temperatures.