THE USE OF ISOMETRIC-EXERCISE AS A MEANS OF EVALUATING THE PARASYMPATHETIC CONTRIBUTION TO THE TACHYCARDIA INDUCED BY DYNAMIC EXERCISE IN NORMAL MAN
THE USE OF ISOMETRIC-EXERCISE AS A MEANS OF EVALUATING THE PARASYMPATHETIC CONTRIBUTION TO THE TACHYCARDIA INDUCED BY DYNAMIC EXERCISE IN NORMAL MAN
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DOI：
10.1007/bf00583741
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发表时间：
1988-07-01
影响因子：
4.5
通讯作者：
MANCO, JC
中科院分区：
文献类型：
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作者：
GALLO, L;MACIEL, BC;MANCO, JC
对14名正常受试者进行等长运动（IE）、动力运动（DE）及两者联合（IE + DE）。本研究的主要目的是利用IE作为评价DE引起心率（HR）增加的机制的一种手段。为此，标准化IE（手柄）的大小，以便几乎完全通过迷走神经收缩引起HR升高：使用动力计应变计系统进行IE，在最大自主收缩（MVC）的75%下线性响应10 s，以1 min间隔重复。在控制条件下，IE诱发的HR的变化进行了比较，诱发DE期间，并在相应的恢复期。DE由腿部进行，受试者在坐姿下保持4分钟，工作负荷为55和105瓦，间隔休息时间。在联合方案中，在DE开始时，DE期间1、2、3 min，恢复期0、1、2、3、5 min进行IE。结果表明：（1）IE联合DE引起的心率增快均小于单独IE，且在10 ~（-5）W时比55 W时更明显，提示DE开始时迷走神经收缩依赖于负荷，并持续到运动结束。(2)在DE期间，即使在105 W的负荷下，每个IE也引起相似的HR增加，当HR对DE本身响应逐渐增加时;这些结果表明，这种逐渐的心动过速（从DE的第1分钟到第4分钟）不依赖于山毛榉（3）这里使用的标准化IE允许对迷走神经收缩的动力学进行功能评价，而不需要依赖于自主神经的药物阻断。神经系统
Fourteen normal subjects were submitted to isometric exercise (IE), dynamic exercise (DE) and a combination of the two (IE + DE). The main purpose of the present was to use IE as a means of evaluating the mechanism of the heart rate (HR) increase induced by DE. To this end, the magnitude of the IE (handgrip) was standardized so as to cause an elevation of HR almost exclusively by vagal withdrawal: IE was performed sing a dyhnamometer strain-gauge system with a linear response at 75% of maximal voluntary contraction (MVC)for 10 s, repeated at 1 min intervals. The change in HR evoked by IE under control conditions was compared with that evoked during DE, and during the corresponding recovery period. DE was performed by the legs, with the subject in the seated position for 4 min, at workloads of 55 and 105 watts, separated by a rest period. In the combined protocol, IE was peformed at the beginning of DE, as well as at 1, 2 and 3 min during DE, and at 0, 1, 2, 3 and 5 min during recovery period. The following results were obtained: (1) IE associated with DE always induced smaller increase in heart rate than IE alone, and this effect was more marked at 10-5 than at 55 W; this finding suggested a workload-dependent vagal withdrawal at the very beginning of DE that was sustained until the end of effort. (2) During DE, each IE induced a similar increase in HR, even at workload of 105 W, when the HR increased gradually in response to DE itself; these results suggest that, this gradual tachycardia (from the 1st to the 4th min of DE) was not fagus dependent (3)The standardized IE used here permitted functional evaluation of the dynamics of vagal withdrawal without resorting to pharmacological blockade of the autonomic nervous system.