Yasuda Y, Ishida K, Miyamura M
Research Center of Physical Fitness, Sports and Health, Toyohashi University of Technology, Japan.
Jpn J Physiol. 1992;42(2):233-37. doi: 10.2170/jjphysiol.42.223.
Changes in the time courses of VO2 during constant-load exercise were examined in connection with other cardiorespiratory and blood chemical parameters. Eleven healthy male subjects performed a ramp exercise and three to six constant-load exercises at varying degrees of load using an electro-braked bicycle ergometer. Heart rate, ventilation, and gas exchange were measured during both types of exercise, and chemical parameters of the subject's blood (blood gas, pH, lactate, and electrolytes) were determined during two intensities of constant-load exercise. The time courses of cardiorespiratory and blood chemical data 3 min after the onset of constant-load exercise were fitted by linear regressions to see whether these parameters had reached the steady state or not. Heart rate increased significantly at a lower intensity of constant-load exercise than VE, VO2, and VCO2. While the increase in VCO2 was slower than that of VO2, a definite difference in time courses was not found between VE and VO2. The time courses of changes in blood gas, pH, bicarbonate, and lactate were not correlated with those of VO2. However, changes in blood potassium concentration were closely correlated with those of VO2 in terms of time courses and magnitude. This suggests the possibility that blood potassium may play an important role in the control of VO2 time course during constant-load exercise.
在恒负荷运动期间，对VO₂时间进程的变化与其他心肺和血液化学参数进行了关联研究。11名健康男性受试者使用电动刹车自行车测力计进行了一次递增运动和三到六次不同负荷程度的恒负荷运动。在两种运动类型期间均测量心率、通气和气体交换，并在两种恒负荷运动强度期间测定受试者血液的化学参数（血气、pH值、乳酸和电解质）。通过线性回归拟合恒负荷运动开始后3分钟的心肺和血液化学数据的时间进程，以观察这些参数是否已达到稳态。在恒负荷运动强度较低时，心率比VE、VO₂和VCO₂显著增加。虽然VCO₂的增加比VO₂慢，但在VE和VO₂之间未发现时间进程上的明显差异。血气、pH值、碳酸氢盐和乳酸的变化时间进程与VO₂的变化时间进程不相关。然而，血钾浓度的变化在时间进程和幅度方面与VO₂密切相关。这表明血钾可能在恒负荷运动期间VO₂时间进程的控制中起重要作用。
