Field study on effect of large temperature steps on thermal comfort and physiological response in severe cold climate

Big environmental difference between the artificial indoor environments and the outdoor environments affects human comfort and physiological responses. This study examines the dynamic changes in human psychological and thermal responses to sudden, large temperature differences under three indoor conditions: slightly warm, neutral, and slightly cold. The similarities and differences between field studies and existing laboratory research were also analyzed. The results indicated that the indoor-outdoor temperature differences under slightly cold, neutral, and slightly warm conditions were 24.5 degrees C, 32.6 degrees C, and 39 degrees C. Environmental differences between indoor and outdoor conditions were influenced by various factors, including temperature, air speed and so on. Human thermal responses differed significantly among the three conditions (P < 0.01). Thermal sensation vote (TSV), thermal comfort vote (TCV), and skin temperature showed great changes after the environmental shift. Skin temperature fluctuated more during down-step, while heart rate and heart rate variability (HRV) exhibited greater changes during up-step in this test. In real-world scenarios, human thermal responses were influenced by temperature, air speed, and human behavior, resulting in deviations from laboratory findings. Furthermore, a time-dependent model for skin temperature and TSV was developed, revealing that thermal sensation changes more rapidly than skin temperature during abrupt shifts from cold to near-neutral environments.