Department of Rehabilitation Medicine, St. Marianna University School of Medicine Yokohama City Seibu Hospital, Yokohama 241-0811 Japan.
Department of Rehabilitation Sciences, Kitasato University Graduate School of Medical Sciences, Sagamihara 252-0373, Japan.
Int J Environ Res Public Health. 2019 Aug 8;16(16):2838. doi: 10.3390/ijerph16162838.
A simplified substitute for heart rate (HR) at the anaerobic threshold (AT), i.e., resting HR plus 30 beats per minute or a percentage of predicted maximum HR, is used as a way to determine exercise intensity without cardiopulmonary exercise testing (CPX) data. However, difficulties arise when using this method in subacute myocardial infarction (MI) patients undergoing beta-blocker therapy. This study compared the effects of αβ-blocker and β1-blocker treatment to clarify how different beta blockers affect HR response during incremental exercise. MI patients were divided into αβ-blocker ( = 67), β1-blocker ( = 17), and no-β-blocker ( = 47) groups. All patients underwent CPX one month after MI onset. The metabolic chronotropic relationship (MCR) was calculated as an indicator of HR response from the ratio of estimated HR to measured HR at AT (MCR-AT) and peak exercise (MCR-peak). MCR-AT and MCR-peak were significantly higher in the αβ-blocker group than in the β1-blocker group ( < 0.001, respectively). Multiple regression analysis revealed that β1-blocker but not αβ-blocker treatment significantly predicted lower MCR-AT and MCR-peak (β = -0.432, < 0.001; β = -0.473, < 0.001, respectively). Based on these results, when using the simplified method, exercise intensity should be prescribed according to the type of beta blocker used.
一种简化的无氧阈（AT）替代心率（HR）的方法，即静息 HR 加 30 次/分钟或预测最大 HR 的百分比，可用于在没有心肺运动测试（CPX）数据的情况下确定运动强度。然而，当在接受β受体阻滞剂治疗的亚急性心肌梗死（MI）患者中使用这种方法时，会出现一些困难。本研究比较了αβ受体阻滞剂和β1受体阻滞剂治疗的效果，以阐明不同的β受体阻滞剂如何影响递增运动中的 HR 反应。MI 患者分为αβ受体阻滞剂（n = 67）、β1受体阻滞剂（n = 17）和无β受体阻滞剂（n = 47）组。所有患者在 MI 发病后一个月接受 CPX。代谢变时关系（MCR）作为 HR 反应的指标，通过 AT（MCR-AT）和峰值运动（MCR-peak）时估计 HR 与实测 HR 的比值计算。与β1受体阻滞剂组相比，αβ受体阻滞剂组的 MCR-AT 和 MCR-peak 显著更高（均<0.001）。多元回归分析显示，β1受体阻滞剂而不是αβ受体阻滞剂治疗显著预测 MCR-AT 和 MCR-peak 较低（β=-0.432，<0.001；β=-0.473，<0.001）。基于这些结果，在使用简化方法时，应根据所使用的β受体阻滞剂类型来规定运动强度。
