Behavioral adaptations to cold environments: A comparative study of active nomadic and modern sedentary lifestyles

Modern occupants hardly use their capacity to adapt to the wide range of thermal environments due to living in well-insulated buildings with indoor climatization. However, climate change with associated health hazards necessitates exploring the limits of human adaptability to extreme environments. Thus, this work compared the adaptive actions of Tuvan nomads living in lightweight yurts in Siberia and modern sedentary dwellers from the Netherlands. The descriptive analysis focused on differences in behavior, thermal exposure, and comfort expectations. Body accelerometry, skin, and exposure temperature were monitored over 3 days in wintertime using wearable sensors, while the indoor environment was monitored using stationary sensors. A significant difference in the daytime lifestyle between the Dutch and the Tuvans was reflected in the time spent indoors (66–100% vs. 15–51%), frequency of going outdoors (1–6 vs. 6–25 times), and the indoor clothing fashion (<1 clo vs. 1.1–2.3 clo). The nomadic population was exposed to a greater variation of the thermal environment (from -30 °C to +40 °C) in contrast to the Dutch (from 21 to 26 °C). Skin temperatures and the estimated Predictive Mean Vote (PMV) index indicated that Tuvans were relatively warm indoors than the Dutch, despite cold outdoors (mean -22 °C). The combination of greater clothing insulation, greater overall daily activity, elevated metabolic rate, and occasional overheating indoors defined such a difference. Nomads mainly relied on their actions rather than housing to keep themselves warm, and they had modest expectations of comfort, making them accept wider temperature variations, which was the crucial difference from modern expectations.