School of Sport and Exercise Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
J Physiol. 2013 Aug 1;591(15):3777-88. doi: 10.1113/jphysiol.2013.254722. Epub 2013 May 27.
We elucidated the autonomic mechanisms whereby heart rate (HR) is regulated by the muscle metaboreflex. Eight male participants (22 ± 3 years) performed three exercise protocols: (1) enhanced metaboreflex activation with partial flow restriction (bi-lateral thigh cuff inflation) during leg cycling exercise, (2) isolated muscle metaboreflex activation (post-exercise ischaemia; PEI) following leg cycling exercise, (3) isometric handgrip followed by PEI. Trials were undertaken under control (no drug), β1-adrenergic blockade (metoprolol) and parasympathetic blockade (glycopyrrolate) conditions. HR increased with partial flow restriction during leg cycling in the control condition (11 ± 2 beats min(-1); P < 0.05). The magnitude of this increase in HR was similar with parasympathetic blockade (11 ± 2 beats min(-1)), but attenuated with β-adrenergic blockade (4 ± 1 beats min(-1); P < 0.05 vs. control and parasympathetic blockade). During PEI following leg cycling exercise, HR remained similarly elevated above rest under all conditions (11 ± 2, 13 ± 3 and 9 ± 4 beats min(-1), for control, β-adrenergic and parasympathetic blockade; P > 0.05 between conditions). During PEI following handgrip, HR was similarly elevated from rest under control and parasympathetic blockade (4 ± 1 vs. 4 ± 2 beats min(-1); P > 0.05 between conditions) conditions, but attenuated with β-adrenergic blockade (0.2 ± 1 beats min(-1); P > 0.05 vs. rest). Thus muscle metaboreflex activation-mediated increases in HR are principally attributable to increased cardiac sympathetic activity, and only following exercise with a large muscle mass (PEI following leg cycling) is there a contribution from the partial withdrawal of cardiac parasympathetic tone.
我们阐明了心率（HR）受肌肉代谢反射调节的自主机制。八名男性参与者（22 ± 3 岁）进行了三项运动方案：（1）在腿部循环运动期间通过双侧大腿袖带充气增强代谢反射激活，（2）腿部循环运动后的孤立肌肉代谢反射激活（PEI），（3）等长握力后进行 PEI。在控制（无药物）、β1 肾上腺素能阻断（美托洛尔）和副交感神经阻断（格隆溴铵）条件下进行试验。在控制条件下，腿部循环期间部分血流量限制会导致 HR 增加（11 ± 2 次/分钟；P < 0.05）。在副交感神经阻断的情况下，HR 增加的幅度相似（11 ± 2 次/分钟），但在β肾上腺素能阻断的情况下减弱（4 ± 1 次/分钟；P < 0.05 与控制和副交感神经阻断）。在腿部循环运动后的 PEI 期间，在所有条件下 HR 均保持高于静息水平（控制、β 肾上腺素能和副交感神经阻断分别为 11 ± 2、13 ± 3 和 9 ± 4 次/分钟；P > 0.05 之间的条件）。在手握后进行 PEI 时，在控制和副交感神经阻断条件下 HR 均从静息状态升高（4 ± 1 与 4 ± 2 次/分钟；P > 0.05 之间的条件），但在β肾上腺素能阻断的情况下减弱（0.2 ± 1 次/分钟；P > 0.05 与休息）。因此，肌肉代谢反射激活介导的 HR 增加主要归因于心脏交感神经活动的增加，只有在进行大量肌肉运动（腿部循环后的 PEI）时，才会从心脏副交感神经张力的部分撤回中得到贡献。
