Changes in related heart rate variability indicators and vital signs of aviators flying 3 different types of aircraft at a simulated altitude of 7 500 meters

Abstract

Objective To investigate the effects of simulated 7 500 high altitude on the changes of such related indicators as heart rate variability(HRV), heart rate (HR), respiratory rate, body surface temperatures (BST), arterial oxygen saturation (SaO2) and blood pressure (BP) of the aviators flying 3 different types of aircraft. Methods Forty-nine aviators were chosen as research subjects, and were divided into 3 groups in accordance with the different types of aircraft they flew. Changes in HRV and other vital signs were observed in the aviators flying 3 different types of aircraft. Results As compared with that before hypoxia exposure, HR and BST of the aviators flying different types of aircraft were significantly increased, 3 minutes after exposure to hypoxia (P 0.05). Before exposure, the values of low frequency (LF), high frequency(HF)and total power (TP) of the aviators flying bombers were all obviously higher than those after exposure (P<0.05). The LF value before hypoxia was significantly higher than that of the aviators flying transports (P<0.05). Both before and after hypoxia, body surface temperature of the aviators flying fighters [(32.05±1.16)、(32.69±0.87)℃] was all significantly higher than that of the aviators flying bombers [(30.45±2.13)、(31.76±1.05)℃] (P<0.05). Following exposure to hypoxia, the maximum A and minimum mean HRB difference of the aviators flying fighters was significantly higher than that before hypoxia exposure (P<0.01). Following exposure to hypoxia, the maximum mean respiratory rate of the aviators flying fighters was obviously decreased (P<0.05), and the maximum and minimum mean respiratory rate difference of the aviators was significantly lower than that before hypoxia exposure (P<0.05). Conclusions Following hypoxia for 3 minutes at a simulated altitude of 7 500 meters, HR and BST of the aviators in the 3 groups were all increased, SaO2 and respiratory rate were decreased, but BP was not significantly increased. There were variable differences in vital signs and HRV for the aviators flying different types of aircraft. Key words: Aviator; Hypoxia; Vital signs; Heart rate variability