| Autor: |
Xu X; Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States., Rioux TP; Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States., Castellani JW; Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States., Montain SJ; Montana Center for Work Physiology and Exercise Metabolism, College of Health, The University of Montana, Missoula, Montana, United States., Charkoudian N; Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States. |
| Abstrakt: |
Rising global temperatures, driven by climate change, pose a threat to human health and regional livability. Empirical data and biophysical model-derived estimates suggest that the critical environmental limits (CELs) for livability are dependent on ambient temperature and humidity. We use a well-validated, physiology-based, six-cylinder thermoregulatory model (SCTM) to independently derive CELs during sustained minimal, light, and moderate activity across a broad range of ambient temperatures and humidity levels and compare with published data. The activity and environments were considered livable if predicted core temperatures did not reach 38 ± 0.25°C within 6 h. The outcomes for minimal activity revealed CELs ranging from 34°C/95% relative humidity (RH) to 50°C/5% RH. Corresponding dry heat losses ranged from 14 to -72 W·m -2 (negative = heat gain) and evaporative heat losses ranged from 39 to 104 W·m -2 . The wet-bulb temperature ( T wb ) at the CELs ranged from 33.3°C to 20.9°C. Activity shifted CELs toward lower temperatures and humidities. Importantly, our predicted CELs largely agree with observed livability CELs from physiology and those from a biophysical model. The physiology-grounded SCTM has utility for assessing the impact of climate change on regional livability. NEW & NOTEWORTHY This study is the first to use a physiology-grounded thermoregulatory model to predict critical environmental limits (CELs) above which human thermoregulatory capacity is exceeded. The model outcomes closely approximate empirically derived CELs, showing it is a strong model for estimating and preparing for the impact of climate warming on local, regional, and world human population livability and migration. |
