Human skin thermography-a descriptive analysis

Human skin temperature (T-sk) is significant for controlling thermogenesis and maintaining a suitable gradient of heat exchange between the body core and shell. The study explored skin surface infra-red thermographic profiles of a sample of 349 male and 424 female volunteers in rural areas at climatic exposures 22.3 +/- 1.8, 27.2 +/- 1.4 and 33.1 +/- 2.7 degrees C WBGT (Wet Bulb Globe Temperature). Cartographic analysis of formulae used to estimate weighted revealed that the reference obtained from infrared thermography was more accurate in real-life climate-human response assessment. The magnitudes of local T-sk and the reference remained very similar for both males and females. The increasing trend of T-sk with a corresponding environmental load indicates the space of thermoregulatory adjustment. The T-sk of local areas at 22.3 to 33.1 degrees C WBGT varied from 32.7 +/- 4.8 to 36.6 +/- 1.1 degrees C (male) and 33.5 +/- 2.9 to 36.8 +/- 1.0 degrees C (female), respectively. A large spread (32.7-36.3 degrees C) of local T-sk at WBGT of 22.3 +/- 1.8 degrees C gradually tended to converge at higher exposures. T-sk of the forehead, front, and back clustered at the higher range, and in contrast, T-sk of extremities-hand (palm), feet, and lower leg pressed lower at all ambient exposures. The analysis indicated that infra-red thermography of human skin surfaces is a straightforward approach for large-scale screening and strategically safeguarding the population from adverse climate exposures. About the prevailing climatic stress during the hot and humid summer, a reference below the levels of 35.7 degrees C for males and 36 degrees C for females would be appropriate as the permissible cut-off limit for exposure to avoid ensuing heat illness.