Vanfraechem J H
J Appl Physiol Respir Environ Exerc Physiol. 1979 Mar;46(3):588-92. doi: 10.1152/jappl.1979.46.3.588.
By use of the impedance noninvasive method, cardiac output (Q), stroke volume (SV), heart rate (HR), Heather index (HI), and systolic time interval (STI) values were studied in 17 subjects working at 25, 50, and 75% of their maximal oxygen uptake (Vo2 max) on a Monark bicycle. A significant increase in SV at each work load and a concomitant decrease in positive expiratory pressure (PEP), left ventricular ejection time (LVET), and PEP/LVET were observed. The linear regression equation at 75% Vo2 max between LVET and HR and SV confirms the close relationship between these parameters. The significa-t increase of the contractility index (HI) showing the stress response of the myocardium is clearly assessed. At 75% work load, its correlation with SV is low; but the high level of the correlation (r = 0.90) between HI and HR in the stress response. Consequently the changes in STI and HI provide valuable information on SV adjustment during calibrated effort responses. Consequently, the changes in STI and HI, the relationship between STI and SV, and the study of SV, HR, and Q provide valuable information about the adjustment of these parameters during calibrated efforts.
通过使用阻抗无创方法，对17名受试者在Monark自行车上以其最大摄氧量（Vo2 max）的25%、50%和75%进行运动时的心输出量（Q）、每搏输出量（SV）、心率（HR）、希瑟指数（HI）和收缩期时间间期（STI）值进行了研究。观察到在每个工作负荷下SV显著增加，同时呼气末正压（PEP）、左心室射血时间（LVET）和PEP/LVET降低。在75%Vo2 max时LVET与HR和SV之间的线性回归方程证实了这些参数之间的密切关系。心肌应激反应的收缩性指数（HI）显著增加得到了明确评估。在75%工作负荷下，其与SV的相关性较低；但在应激反应中HI与HR之间的相关性较高（r = 0.90）。因此，STI和HI的变化在校准运动反应期间为SV调节提供了有价值的信息。因此，STI和HI的变化、STI与SV之间的关系以及对SV、HR和Q的研究在校准运动期间为这些参数的调节提供了有价值的信息。
