Effect of Altitude Difference on Human Physiologic Indexes in Visual Work

摘要

In recent years, there has been increasing a traffic circumstance enabling spontaneous move to high altitude but, for human beings; it is not easy to adjust themselves to the high altitude, increasing physical stress on them. Under such circumstance, the authors made an investigation on the specific factors of change in the physical stress under the working environment in driving work, etc. at a high altitude by examining the extent of variation in physiologic indexes under hypobaric environment. The subjects participated in the experience were 13 healthy male students proved to have no problem through health checkup and doctor's questions. They had a simulation of rapid ascent from level ground to high altitude in an environmental chamber, after which a visual task was imposed on them and their physiologic variation was measured, centered on the cardiovascular parameters. As a result, at an altitude environment of 5,000m simulated in the environmental chamber, their blood oxygen saturation lowered significantly in comparison with that at level ground and their regional cerebral oxygen saturation showed a down tendency. The patterns in cerebral oxygen saturation (rSO2) and cerebral blood volume change (HbI) were in completely the opposite direction. In addition, the heart rate was increased and the involvement of respiratory factor was recognized; it was also observed that the number of eye blinks differed slightly even in the same visual task. It proved that the extent of physical stress accompanying a rapid altitude change is quite serious as explained in the results of Subjective Symptom, Japan Society for Occupational Health. It would be required to have proper understanding of risk factors in making a spontaneous move to high altitude.