Physiological and perceptual responses of exposure to different altitudes in extremely cold environment

Abstract

An increasing number of people are living or working at high altitudes, which are often accompanied by cold environments. High altitude and cold exposure often result in physiological, perceptual and biochemical changes, thus affecting work efficiency and even human health. This study created different altitude conditions of 0 m, 2560 m, 3650 m, and 4290 m with an ambient temperature of −10 °C in a climate chamber. Six health subjects were recruited, and human physiological and perceptual responses during this experiment were continuously investigated, involving objective parameters such as core temperature, local skin temperature, blood oxygen saturation, heart rate, respiratory rate and subjective parameters such as overall and local thermal sensation, overall and local thermal comfort. The statistical analysis showed that blood oxygen saturation is the most sensitive parameter in short exposure to high altitude, which is consistent with previous studies and shows a close relationship with altitude. All of the mean local skin temperatures in the face, hands and feet throughout the experimental period were lowest at 0 m altitude. The overall thermal sensation decreased by 2.83 units at 0 m, whereas it decreased by only 2.00 units at an altitude of 4290 m. The local thermal sensation correlated well with the local skin temperature (R2 > 0.8) at 0 m, 2560 m and 3650 m when the subjects keep sedentary and wear clothing ensemble with total insulation of 2.16 clo. At an altitude of 4290 m, the local thermal sensations of the face, hands and feet were close to 0 (neutral). These findings indicate that higher altitude may compensate for some of the decreases in thermal sensation caused by a cold environment.