Alterations of biochemical indicators in military personnel with different endurance qualities before and after high altitude exposure

To explore the changes in biochemical indicators among soldiers with different endurance qualities after high altitude exposure and their adaptation to plateau environment.

A status survey was carried out on 253 young male soldiers who were planned to station in Malone, Yunnan Province（2 100 m）for 4 weeks from July to August, 2018. The sampling method is cluster sampling. The endurance quality and biochemical indicators were assessed and measured before exposure and after 4 weeks' training. Their endurance quality was evaluated with grading 3-km armed cross-country. The included biochemical indicators were levels of creatine kinase, hemoglobin, average hemoglobin and cardiac troponin, and counts of blood red cells, lymphocytes and basophils.

Based on the results of the 3-km armed cross-country, the participants were divided into excellent（12%）, good（21%）, passing（40%）and failing（27%）groups. Except for basophil counts, levels of creatine kinase, cardiac troponin, hemoglobin and average hemoglobin, and counts of red blood cells and lymphocyte changed significantly in all the 4 groups before and after high altitude exposure（P<0.01）. While, obvious changes were observed in cardiac troponin level and lymphocyte count among the 4 groups after they were stationed at high altitude（P<0.01）, and these changes were correlated with endurance quality（cardiac troponin: r_s=-0.409, P<0.01; lymphocytes: r_s=0.205, P<0.01）.

There are some differences in blood biochemical indicators in soldiers with different endurance qualities at high altitude. Our results suggest that soldiers with higher endurance quality have a relatively lower risk of myocardial injury and stronger immune function after entering high altitude.