Kinetics of respiratory and circulatory responses to step, impulse, sinusoidal and ramp forcings of exercise load in humans.
Kinetics of respiratory and circulatory responses to step, impulse, sinusoidal and ramp forcings of exercise load in humans.
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人类运动负荷的步进、脉冲、正弦和斜坡强迫的呼吸和循环反应动力学。
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发表时间：
1992
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通讯作者：
Y. Miyamoto
中科院分区：
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作者：
Y. Miyamoto
本文研究了健康人在中等负荷范围内每分钟通气量（VE）、耗氧量（VO2）、二氧化碳排出量（VCO2）、心输出量（Q）和心率（HR）对阶跃、脉冲、正弦和斜坡运动负荷变化的瞬态反应。使用自行车测力计在直立位置进行锻炼。对阶跃和脉冲强迫的瞬态响应基本上符合由快分量和慢分量组成的二阶模型，而对正弦和斜坡强迫的响应符合一阶模型。没有观察到显着的不对称性之间的开和关响应阶跃强迫。相反，变量的平均响应时间（MRT =纯时间延迟+时间常数）上升斜坡强迫延长，而MRT下降斜坡缩短斜坡坡度减小。在VE、VO2和VCO2中观察到MRT的开关不对称性，在较小程度上，在HR和Q中也观察到MRT的开关不对称性。一个非线性的血流模型，它模拟了代谢物质的洗入和洗出时间的变化，进入和从化学感受器，已被提出作为一个可能的解释不对称的反应。结论是，呼吸和循环的调节系统在其操作中可能基本上是非线性的，尽管事实上，在运动期间的心肺反应似乎适合线性模型。
Transient responses of minute ventilation (VE), oxygen consumption (VO2), carbon dioxide output (VCO2), cardiac output (Q) and heart rate (HR) to step, impulse, sinusoidal and ramp changes in exercise load were studied in healthy human subjects at the moderate load range. Exercise was performed in the upright position using a bicycle ergometer. The transient responses to step and impulse forcings fitted essentially to a second-order model consisting of a fast and a slow component, while the responses to sinusoidal and ramp forcings fitted to a first-order model. No significant asymmetry was observed between the on- and off-responses to step forcing. On the contrary, the mean response time (MRT = pure time delay + time constant) of variables to ascending ramp forcing was prolonged, while the MRT to descending ramp was shortened with decreasing ramp slope. The on- and off asymmetry of the MRT was observed in VE, VO2 and VCO2 and, to a lesser extent, also in HR and Q. A non-linear blood flow model, which simulates changes in the wash-in and wash-out time of metabolic substances into and from the chemoreceptor, has been proposed as a likely explanation for the asymmetrical responses. It was concluded that the regulatory system of respiration and circulation might be essentially non-linear in its operation, despite the fact that the cardiorespiratory responses during exercise seemed to fit linear models.