Fisher James P, White Michael J
School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Exp Physiol. 2004 Nov;89(6):639-46. doi: 10.1113/expphysiol.2004.028639. Epub 2004 Sep 13.
The cardiovascular response to isometric exercise is governed by both central and peripheral mechanisms. Both metabolic and mechanical stresses on the exercising skeletal muscle produce cardiovascular change, yet it is often overlooked that the afferent signal arising from the muscle can be modified by factors other than exercise intensity. This review discusses research revealing that muscle fibre type, muscle mass and training status are important factors in modifying this peripheral feedback from the active muscles. Studies in both animals and humans have shown that the pressor response resulting from exercise of muscle with a faster contractile character and isomyosin content is greater than that from a muscle of slower contractile character. Athletic groups participating in training programmes that place a high anaerobic load on skeletal muscle groups show attenuated muscle afferent feedback. Similarly, longitudinal studies have shown that specific local muscle training also blunts the pressor response to isometric exercise. Thus it appears that training may decrease the metabolic stimulation of muscle afferents and in some instances chronic exposure to the products of anaerobic metabolism may blunt the sensitivity of the muscle metaboreflex. There may be surprising parallels between the local muscle conditions induced in athletes training for longer sprint events (e.g. 400 m) and by the low-flow conditions in, for example, the muscles of chronic heart failure patients. Whether their similar attenuations in muscle afferent feedback during exercise are due to decreased metabolite accumulation or to a desensitization of the muscle afferents is not yet known.
心血管系统对等长运动的反应受中枢和外周机制的共同调控。运动骨骼肌所承受的代谢和机械应力均会引发心血管系统的变化，但人们常常忽略一点，即来自肌肉的传入信号会受到运动强度以外的其他因素影响。本综述探讨了相关研究，这些研究表明肌纤维类型、肌肉质量和训练状态是调节来自活跃肌肉的外周反馈的重要因素。动物和人类研究均显示，具有较快收缩特性和异肌球蛋白含量的肌肉运动所引发的升压反应，要大于收缩特性较慢的肌肉运动所引发的反应。参与对骨骼肌群施加高无氧负荷训练计划的运动员群体，其肌肉传入反馈减弱。同样，纵向研究表明，特定的局部肌肉训练也会减弱对等长运动的升压反应。因此，训练似乎可能会降低肌肉传入神经的代谢刺激，并且在某些情况下，长期接触无氧代谢产物可能会减弱肌肉代谢反射的敏感性。在为较长距离短跑项目（如400米）进行训练的运动员所诱发的局部肌肉状况，与例如慢性心力衰竭患者肌肉中的低血流状况之间，可能存在惊人的相似之处。运动期间它们的肌肉传入反馈出现类似减弱，究竟是由于代谢产物积累减少还是肌肉传入神经脱敏，目前尚不清楚。
