Effects of rapid and progressive ascent to Tibet plateau on cardiovascular function and stress factors of pre-selected expeditioners for Chinese Antarctic expedition for Kunlun station

Abstract

Objective: To explore the different effects of rapid and progressive ascent to Tibet plateau on cardiovascular function and stress factors in pre-selected expeditioners for the 31st, 32nd and 33rd Chinese Antarctic expedition for inland station, to provide a scientific basis for the selection of qualified expeditioners. Methods: A total of 85 pre-selected expeditioners for the 31st, 32nd and 33rd Chinese Antarctic expedition for Kunlun station were enrolled in this study. According to the different manners of entering the plateau, they were divided into the rapid ascent group by aircraft (RAG, n=55) and the progressive ascent group by train (PAG, n=30). Hemodynamics and electrocardiogram were examined at 4 m (Shanghai), areas at altitude of 3 658 m (Lhasa) and 4 300 m(Yangbajain), respectively. Saliva levels of stress factors, including testosterone (T), cortisol (COR) and immunoglobulin A (IgA), were tested by ELISA. Results: The heart rates (HR) were increased significantly, while the SpO2 was decreased significantly in the two groups within 24 hours at altitudes of 3 658 m and 4 300 m (P＜0.05), while there was no significant difference between the two groups at the same altitude. Compared with 4 m, the blood pressure (BP) of the two groups at 3 658 m and 4 300 m was significantly increased (P＜0.05), and some indexes of myocardial contraction and pumping function were significantly reduced (P＜0.05). However, due to the increase of HR, there was no significant change in Cardiac Output (CO). At 4 300 m, the Thoracic Fluid Content (TFC) of the rapid ascent group was significantly higher than that of the progressive ascent group (P＜0.05). Compared with 4m, there was no significant difference in salivary testosterone change between the two groups at 3 658 m above sea level (P＞0.05), while COR and IgA changes in the rapid ascent group were significantly higher than those in another group (P＜0.05). Conclusion: Compared with the progressive ascent by train,expeditioners that rapid ascent to high altitude have significant effects on cardiovascular function and the stress hormones and immunoglobulin levels in saliva. It's suggested that hypoxia adaptation before Antarctic expediting for Kunlun Station could ensure the selected expeditioners' physical and psychological health, so that the mission could be finished smoothly.