On-site measurement and mediation analysis of physiological parameters and thermal comfort under different outdoor microclimates in a cold region

This study examined the physiological responses and thermal comfort of ten subjects (five females and five males) across five outdoor locations on the campus of Hebei University of Technology during winter. Physiological parameters, including heart rate, LF/HF values from ECG, and α, β, θ values from EEG, were assessed. It revealed significant differences in microclimatic parameters and physiological responses among measurement points. Mean heart rate variations reached up to 5.72 (6.72 %) and mean β values differed by up to 0.05 (26.32 %), 0.08 (47.06 %), and 0.10 (43.48 %) during T1, T2, and T3 periods. HR, α, and θ values positively correlated with TCV, with coefficients of 0.131 (p < 0.01), 0.081 (p < 0.01), and 0.018, while LF/HF and β showed negative correlations, with coefficients of −0.109 (p < 0.01) and − 0.024 (p < 0.01). Changes in TCV from 0 to −2 corresponded to HR, LF/HF, α, β, and θ variations of 6.69 %, −3.5 %, 12.5 %, −9.38 %, and 7.14 %, respectively. Regarding microclimatic parameters' impact on thermal comfort, β in EEG signals showed greater mediating effects than other physiological parameters. This study is useful for providing guidelines for outdoor activities in winter and developing more accurate physiological parameter monitoring and comfort assessment methods.