Exercise Physiology and Biochemistry Laboratory, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres, Greece.
Am J Physiol Heart Circ Physiol. 2010 Dec;299(6):H2090-6. doi: 10.1152/ajpheart.00087.2010. Epub 2010 Oct 15.
The aims of the present study were to assess in obese and lean boys 1) the hemodynamic responses and baroreflex sensitivity (BRS) to isometric handgrip exercise (HG) and recovery and 2) the muscle metaboreflex-induced blood pressure response and the variables that determine this response. Twenty-seven boys (14 obese and 13 lean boys, body mass index: 29.2 ± 0.9 vs. 18.9 ± 0.3 kg/m(2), respectively) participated. The testing protocol involved 3 min of baseline, 3 min of HG (30% maximum voluntary contraction), 3 min of circulatory occlusion, and 3 min of recovery. The same protocol was repeated without occlusion. At baseline, no differences were detected between groups in beat-to-beat arterial pressure (AP), heart rate (HR), and BRS; however, obese boys had higher stroke volume and lower total peripheral resistance than lean boys (P < 0.05). During HG, lean boys exhibited higher HR and lower BRS compared with their obese counterparts. In lean boys, BRS decreased during HG compared with baseline, whereas in obese boys, it was not significantly modified. In lean boys, TPR was elevated during HG and declined after exercise, whereas in obese boys, TPR did not significantly decrease after exercise cessation. In the postexercise period, BRS in lean boys returned to baseline, whereas an overshoot was observed in obese boys. Postexercise BRS was correlated with body mass index (R = 0.56, P < 0.05). Although the metaboreflex-induced increase in AP was similar between obese and lean children, it was achieved via different mechanisms: in lean children, total peripheral resistance was the main contributor to AP maintenance during the metaboreflex, whereas in obese children, stroke volume significantly contributed to AP maintenance during the metaboreflex. In conclusion, obese normotensive children demonstrated altered cardiovascular hemodynamics and reflex control during exercise and recovery.
本研究旨在评估肥胖和瘦小男孩 1）在等长握力运动（HG）及恢复过程中的血流动力学反应和压力感受性反射敏感性（BRS），2）肌肉代谢反射引起的血压反应及决定该反应的变量。共 27 名男孩（14 名肥胖男孩，13 名瘦小男孩，体重指数分别为 29.2±0.9 和 18.9±0.3kg/m²）参与了研究。测试方案包括 3 分钟基线期、3 分钟 HG（最大自主收缩的 30%）、3 分钟循环闭塞期和 3 分钟恢复期。没有闭塞时，重复相同的方案。在基线期，两组间的心率（HR）、动脉压（AP）和 BRS 无差异；然而，肥胖男孩的每搏输出量高于瘦小男孩，外周总阻力低于瘦小男孩（P＜0.05）。在 HG 期间，与肥胖男孩相比，瘦小男孩的 HR 更高，BRS 更低。与基线相比，瘦小男孩的 BRS 在 HG 期间下降，而肥胖男孩的 BRS 没有明显改变。在瘦小男孩中，HG 期间的 TPR 升高，运动后下降，而在肥胖男孩中，运动停止后 TPR 没有明显下降。在运动后的恢复期，瘦小男孩的 BRS 恢复到基线水平，而肥胖男孩的 BRS 出现了过度反应。运动后 BRS 与体重指数呈正相关（R=0.56，P＜0.05）。尽管肥胖和瘦小男孩的代谢反射引起的 AP 增加相似，但它们是通过不同的机制实现的：在瘦小男孩中，运动后代谢反射期间，总外周阻力是维持 AP 的主要因素，而在肥胖男孩中，SV 显著有助于代谢反射期间的 AP 维持。总之，肥胖的正常血压儿童在运动和恢复期间表现出心血管血流动力学和反射控制的改变。
