逐级增加体力负荷时的呼吸气体交换和无氧代谢阈值

RESPIRATORY GAS EXCHANGE AND ANAEROBIC THRESHOLD DURING INCREMENTAL EXERCISE

对于以呼吸气体交换参数判定无氧代谢阈值至今仍有许多争论。本工作目的在于研究人体在逐级增加负荷量运动期间的气体交换的变化过程;它与血乳酸浓度改变的关系;以及气体交换无氧代谢阈值与体力活动能力,尤其是与耐力活动能力之间的联系,以探讨气体交换无氧代谢阈值的应用价值。受试对象为6名中长跑运动员,6名短跑运动员和10名非运动员,他们在踏车式功量计上以20瓦/分的速率递增负荷量运动直至最大强度。结果表明:(1)当负荷量递增至一定强度时每分通气量、二氧化碳排出量发生非线性增加,此时相应的呼出气二氧化碳浓度无明显改变而呼出气氧浓度增高。上述改变的起始点在大多数受试者上易于辨认,并可由此起始点判定气体交换无氧代谢阈值;(2)气体交换无氧代谢阈值与血乳酸浓度开始明显升高所判定的乳酸无氧代谢阈值之间呈显著正相关(r=0.948,p<0.001);(3)运动员组的气体交换无氧代谢阈值明显高于非运动员组(氧耗量分别为1.86±0.42和1.02±0.32升/分,P<0.05),而中长跑运动员组的无氧代谢阈值又明显高于短跑运动员组(氧耗量分别为2.10±0.24和1.65±0.43升/分,P<0.05)。以上结果提示无氧代谢阈值可以由气体交换参数加以判定。气体交换无氧代谢阈值是评估人体有氧工作能力,特别是耐力活动能力的有效生理指标。

The present study was undertaken to assess the validity of detecting the anaerobic threshold from respiratory gas exchange indices. In 92 male subjects（6 endurance runners, 6 sprinters, and 10 untrained subjects）, we examined: 1) the changes in respiratory gas exchange parameters （VI, FEO2, FECO2, VO2 and VCO2） and in blood lactate concentration during an incremental exercise test for detecting the anaerobic threshold; 2)the correlation between the values of anaerobic threshold determined by gas exchange measurements(ATGE)and by blood lactate concentration (ATLA); 3) the differences in ATGE between athletes and untrained subjects and between endurance runners and sprinters. We found that 1) a characteristic nonlinear increase in VI and VCO2 without a corresponding decrease in FECO2, and, an abrupt increase in lactate concentration exceeding the resting value as the work rate increased were demonstrated in most of the subjects tested. ATGE could be identified by the point of nonlinear increase in VI and VCO2, while ATLA could be defined by the point at which the abrupt increase in blood lactate occurred; 2) ATGE was highly correlated to ATLA （r=0.948, p<0,001）; 3) ATGE was significantly greater in the athletes than in the untrained subjects(1.86±0.42 VS. 1.02±0.32 L. min-1 Vo2,p<0.05).Furthermore, the endurance runners had higher values of ATGE than the sprinters (2.10±0.24 VS.1.65±0.43 L.min-1 Vo2, p<0,05). The data indicate that gas exchange indices provide reliable detection of the anaerobic threshold. Moreover, ATGE seems to be a valid measure for evaluating aerobic work power, particularly applicable to endurance performance.