目的　明确健康人运动时呼吸循环反应及运动前后血钾改变 ,寻找定量评价呼吸困难和求取无氧阈 (AT)的方法。方法　对 43名健康青年男性进行了运动负荷试验 ,测定了气体代谢指标和动脉血钾 ,判定了勃氏分级指数 (BS)和每分钟氧摄取量 ( VO2 )的相关性 ,评价了 5种气体代谢交换法求取的AT。结果　死腔通气率静息时为 0 2 8± 0 0 5 ,最大运动时为 0 19± 0 0 5 ,两者比较P <0 0 1,运动前后动脉血钾分别 3 76mmol/L± 0 2 9mmol/L ,4 10mmol/L± 0 38mmol/L ,两者比较P <0 0 1;BS与 VO2 直线相关 ,得到BS斜率 (BSS)等定量评价呼吸困难指标。不同方法求取的AT ,ATVCO2为 12 0 8ml/min± 2 33ml/min ,ATVE和ATVEO2 与其比较具有一致性 (P >0 0 5 )。结论　健康青年男性运动中通气效率改善 ;运动后动脉血钾增高 ;运动中呼吸困难能够定量评价 ;应用每分钟二氧化碳呼出量 ( VCO2 )、每分钟通气量 ( VE)、氧通气当量 (VEO2 )锐利增加形成拐点求取AT是合适的。 OBJECTIVE: To determine the respiratory responses and changes of serum potassium in healthy subjects before and after exercise, and to find a method for quantitative assessment of dyspnea and determination of anaerobic threshold (AT). Methods Forty - three healthy young men were subjected to exercise stress test. Gas metabolism index and arterial potassium level were measured. Correlation between the Bovine Fractionation Index (BS) and oxygen uptake per minute (VO2) was also evaluated. Five kinds of gases Metabolic exchange method to seek AT. Results The dead space ventilation rate was 0 2 8 ± 0 0 5 at rest and 0 19 ± 0 0 5 at maximum exercise, P <0.01 compared with 3 76 mmol / L ± 0 2 before and after exercise 9 mmol / L, 4 10 mmol / L ± 0 38 mmol / L respectively, P <0 01; BS was correlated with VO2 straight line, and BS slope (BSS) was obtained for quantitative evaluation of dyspnea. The AT and ATVCO2 obtained by different methods were 12 0 8ml / min ± 2 33ml / min and ATVE and ATVEO2 were consistent with each other (P 0 05). Conclusion Ventilation efficiency was improved in healthy young men during exercise. Arterial potassium increased after exercise. Dyspnea during exercise was quantitatively evaluated. VCO2, VE and VEO2 were sharp Increasing the number of inflection points to find AT is appropriate.