Abstract:

In order to explore the characteristics of physiological and thermal sensation changes of construction workers in extreme environments of high temperature, high humidity and low oxygen, under the conditions of ambient temperature (33, 37 40 ℃), relative humidity (80%) and oxygen concentration (20.9%,18%,16%), the participants were organized to carry out treadmill exercise test at a speed of 4 km/h. The effects of these compound environments on the human body were systematically analyzed by measuring physiological parameters, such as mean skin temperature and sweating rate, and psychological parameters, such as fatigue and thermal sensation. The results show that environmental temperature is the primary determinant of physiological responses, but hypoxia under high-temperature conditions significantly amplifies the increase in skin temperature through a significant interaction effect (p<0.05). At 37 ℃, the temperature-rise effect of hypoxia is nearly nine times greater than at 33 ℃. The influence of hypoxia on sweating rate reversed with temperature. Sweating is promoted at 33 ℃, but is inhibited by 10.6% under the extreme high temperature of 40 ℃. Inter-individual variability also increased significantly, with a dispersion increase of 17.4%, which aggravates the risk of heat accumulation. Hypoxia directly accelerated the accumulation of fatigue and thermal discomfort, with 37 ℃ identified as a synergistic critical point (fatigue rate increased by 100% at 33 ℃ and 50% at 37 ℃, and the cumulative slope of thermal discomfort also increased). At 40 ℃, the final fatigue level increases by 38%. The increases in skin temperature in the chest and upper arm are the most sensitive to hypoxia, with increases of 28% to 33%. These regions are key monitoring sites for heat stress warning in high-temperature, high-humidity, and low-oxygen environments.

Key words: high temperature and high humidity, hypoxic environment, physiological parameters, psychological parameters, thermal sensation