Tulppo M P, Mäkikallio T H, Laukkanen R T, Huikuri H V
Department of Medicine, University of Oulu, Finland.
Clin Physiol. 1999 Jul;19(4):294-9. doi: 10.1046/j.1365-2281.1999.00180.x.
Heart rate (HR) is higher during dynamic arm exercise than during leg exercise at equal oxygen consumption levels, but the physiological background for this difference is not completely understood. The vagally mediated beat-to-beat R-R interval fluctuation decreases until the level of approximately 50% of maximal oxygen consumption during an incremental bicycle exercise, but the vagal responses to arm exercise are not well known. Changes in autonomic modulation of HR were compared during arm and leg exercise by measuring beat-to-beat R-R interval variability from a Poincaré plot normalized for the average R-R interval (SD1n), a measure of vagal activity, in 14 healthy male subjects (age 20 +/- 4 years) who performed graded bicycle and arm cranking tests until exhaustion. Seven of the subjects also performed the dynamic arm and leg tests after beta-adrenergic blockade (propranolol 0.2 mg kg-1 i.v.). More rapid reduction occurred in SD1n during the low-intensity level of dynamic arm exercise than during dynamic leg exercise without beta-blockade (e.g. 11 +/- 6 vs. 20 +/- 10 at the oxygen consumption level of 1.2 l min-1; P < 0.001) and with beta-blockade (e.g. 13 +/- 4 vs. 25 +/- 10 at the level of 1.0 l min-1; P < 0.05), and the mean HR was significantly higher during submaximal arm work than during leg work in both cases (e.g. during beta-blockade 81 +/- 12 vs. 74 +/- 6 beats min-1 at the level of 1.0 l min-1; P < 0.05). These data show that dynamic arm exercise results in more rapid withdrawal of vagal outflow than dynamic leg exercise.
在相同耗氧量水平下，动态手臂运动时的心率（HR）高于腿部运动，但这种差异的生理背景尚未完全明确。在递增式自行车运动过程中，迷走神经介导的逐搏R-R间期波动会减小，直至达到最大耗氧量的约50%，但迷走神经对手臂运动的反应尚不清楚。通过测量14名健康男性受试者（年龄20±4岁）在进行分级自行车和手臂曲柄测试直至力竭时，从针对平均R-R间期归一化的庞加莱图（SD1n）中得出的逐搏R-R间期变异性，比较了手臂和腿部运动期间心率自主调节的变化，SD1n是迷走神经活动的一种度量。其中7名受试者在β-肾上腺素能阻滞剂（静脉注射普萘洛尔0.2 mg·kg-1）后还进行了动态手臂和腿部测试。在低强度动态手臂运动期间，SD1n的下降比未使用β-阻滞剂的动态腿部运动更快（例如，在耗氧量为1.2 l·min-1时为11±6 vs. 20±10；P<0.001），使用β-阻滞剂时也是如此（例如，在1.0 l·min-1水平时为13±4 vs. 25±10；P<0.05），并且在两种情况下，次最大强度手臂运动期间的平均心率均显著高于腿部运动（例如，在使用β-阻滞剂时，在1.0 l·min-1水平时为81±12 vs. 74±6次·min-1；P<0.05）。这些数据表明，与动态腿部运动相比，动态手臂运动导致迷走神经传出更快撤离。
