Impacts of indoor and outdoor thermal environments on cardiovascular and cerebrovascular health risks in severe cold regions: A case study

Currently, people are paying more attention to the health demands of the building thermal environment. Research on outdoor climate and disease, as well as indoor thermal environments and discomfort symptoms, has been extensively conducted with considerable breadth and maturity. In contrast, the interrelationship between indoors and outdoors has received comparatively less consideration. On one hand, the correlation between outdoor thermal environment and health risks was examined from perspectives of air temperature (T₀), diurnal temperature range (DTR), and temperature variation (ATV). On the other hand, the relationship between indoor thermal comfort and health risks was analyzed. Additionally, based on local climate and indoor-outdoor correlations, the heating period was studied as a distinct exposure phase. The results show that the distribution of diseases in this area shows regular changes, with the highest incidence occurring in spring and autumn. There is a strong temporal correlation between the period of poor indoor thermal comfort and the stage of increased health risk. A fitting model of T₀ and incidence frequency during the non-heating period was established, revealing that the peak incidence occurs when T₀ range between 4.6 °C and 8.8 °C. T₀, ATV and DTR were all significantly correlated with the incidence frequency during the non-heating period, with correlation coefficients of -0.797, 0.691 and 0.721 respectively. These correlations are notably stronger than those observed in the whole year. Low temperatures and large temperature changes can both increase the health risks.