Objective: To explore the application of the first ventilatory threshold (VT1) and the second ventilatory threshold (VT2) in the classification of physical workload for plateau workers, to provide reference for formulating the classification in plateau. Methods: In August 2018, 88 male workers from substations at different altitudes (500 m, 2000 m, 3000 m and 4000 m) of a company were selected as study subjects by cluster sampling. They were divided into plain group and plateau groups.The intensities of workload were simulated by power bicycle, and physiologic parameters, including VO(2), heart rate (HR) and energy metabolic rate per body surface area (E/BSA) , were recorded in test system when reaching VT1, VT2 and peak oxygen uptake (VO(2)Peak) . The ratios of VT1, VT2 and VO(2)Peak to the quiet and work potential at different altitudes were compared. Results: In a quiet state, compared with the plain group, the HR and E/BSA of the workers in the 2000 m and 3000 m groups increased, and the differences were statistically significant (P<0.05) . At VT2, compared with the plain group, the HR of the workers in the 4000 m group decreased, the difference was statistically significant (P<0.05) . VO(2) and E/BSA of workers in each plateau group were lower than those in the plain group at VO(2)Peak, and the differences were statistically significant (P<0.05) . At VT2 and VO(2)Peak, the ratios of VO(2), HR, and E/BSA relative to the quiet state of the workers in each plateau group were lower than those of the plain group, and the differences were statistically significant (P<0.05) . In the quiet state and VT1, compared with the plain group, the remaining percentages of VO(2) and E/BSA of workers in each plateau group decreased, and the differences were statistically significant (P<0.05) . Taking VT1, VT2 and VO(2)Peak as cut-off points and VO(2), HR and E/BSA as indicators, the physical workload in plateau could be divided into four levels, namely medium, heavy, extremely heavy and extreme physical workload. Conclusion: It is practicable to use ventilatory threshold to classification of physical workload. VT1 and VT2 can be applied to the classification in plateau to supplement and optimize current national standard of physical workload.
目的： 探讨通气无氧阈（VT1）、第二通气无氧阈（VT2）在高原作业人员体力劳动强度分级中的应用，为制定适用于高原环境的体力劳动强度分级标准提供参考。 方法： 于2018年8月，采用整群抽样法抽取某公司不同海拔高度变电站的88名男工为研究对象，分为平原组（500 m组）和各高原组（2 000、3 000、4 000 m组），通过功率自行车模拟不同强度劳动负荷，运动心肺功能测试系统记录平原组和各高原组工人在安静状态时和到达VT1、VT2以及峰值摄氧量（VO(2)Peak）时摄氧量（VO(2)）、心率（HR）、单位体表面积能量代谢率（E/BSA），并比较平原组和各高原组工人在VT1、VT2和VO(2)Peak时相对于安静状态的比值和劳动潜力。 结果： 安静状态时，与平原组比较，2 000 m和3 000 m组工人HR和E/BSA升高，差异均有统计学意义（P<0.05）；VT2时，与平原组比较，4 000 m组工人HR降低，差异有统计学意义（P<0.05）；VO(2)Peak时各高原组工人VO(2)和E/BSA均低于平原组，差异均有统计学意义（P<0.05）。VT2和VO(2)Peak时，各高原组工人VO(2)、HR和E/BSA相对于安静状态的比值均低于平原组，差异均有统计学意义（P<0.05）；在安静状态和VT1时，与平原组比较，各高原组工人VO(2)和E/BSA剩余百分比均降低，差异均有统计学意义（P<0.05）。以VT1、VT2和VO(2)Peak为分界点，VO(2)、HR和E/BSA为指标，可以将高原体力劳动强度分为4个等级，即中等、重、极重和极限体力。 结论： 利用通气阈对体力劳动强度进行分级是可行的，建议将VT1、VT2应用于高原作业工人体力劳动强度分级，以补充和优化我国现行体力劳动强度分级标准。.
Keywords: Anaerobic threshold; Plateau; Ventilatory threshold; Work intensity.