Is there short-term adaptation to repeated thermal stress relief and pleasure? First insights from an experimental study

Dynamic thermal conditions have the potential to support human health and energy efficiency of buildings. However, certain reluctance with respect to the acceptance of such conditions can be observed. While relief and pleasure are considered as components of reward, relief gained little attention within built environmental research. Furthermore, the level of personal control is a known influence on thermal assessment, but its association with perceived relief unknown. Therefore, the objective was to gain insights into the effects of sequences of thermal stress and relief with differing levels of control on thermal sensation, perceived pleasure, perceived relief, and physiological reactions. A laboratory study (N = 60) with 8 sequences of elevated and reduced thermal stress lasting 15 min each, half with reduced, half with increased personal control over thermal environmental conditions was conducted. The data was analysed applying the Bayesian approach to explore effects of these exposures on subjective experience and physiological reactions. Results suggest that the reduction of thermal stress leads to cooler thermal sensation, increased perceived pleasure, and perceived relief (each changing one unit on the 7- and 5-point assessment scale, 0% in the region of practical equivalence (ROPE)), while changes of hand skin temperature (<0.1 K) and heart rate variability were negligible. Over repeated sequences of thermal stress and relief perceived pleasure and possibly relief slightly increased. Despite limitations, this supports a shift towards more dynamic and wide temperature ranges and a more widespread application of Bayesian framework.