Effects of physical training and detraining on sympathetic neural regulation of cardiovascular system

众所周知，体育锻炼可以改善心血管调节，但不清楚运动训练后改善的调节能持续多久。本项目旨在探讨运动过程中在心血管调节中起重要作用的交感神经活动（MSNA）对运动训练和去训练的适应性变化。健康志愿者进行了为期四周的高强度握力训练。在疲劳静态握力训练期间和运动后前臂闭塞（PEFO）后，通过微神经摄影技术记录胫骨神经的MSNA。发现:1。MSNA随握力训练时间的延长而增加，并在疲劳开始时达到最大值。在PEFO期间，MSNA反应大于静息，运动前控制水平2。与训练前相比，训练后疲劳开始时的MSNA反应增加，而训练后对PEFO的MSNA反应不变。经过四周的去训练后，疲劳开始时的MSNA反应与训练后立即的反应相比有所下降，去训练反应的强度在长达一年的时间内保持不变。综上所述，尽管中枢指令和肌肉反射是肌肉收缩过程中增强MSNA的因素，但肌肉代谢反射诱导的对PEFO的MSNA反应的增加并没有被阻力训练调节。另一方面，抗阻训练增加了中央指挥，这一效应短暂地增强了MSNA反应。

It is well known that physical training improves cardiovascular regulation but it is not clear how long the improved regulation persists after exercise training. This project attempted to investigate the adaptive change in sympathetic nervous activity (MSNA), which plays an important role in the control of cardiovascular regulation during exercise, to exercise training and detraining. Healthy volunteers performed high intensity handgrip exercise training for four weeks. MSNA was recorded from the tibial nerve by a microneurography technique during fatiguing static handgrip exercise and following post-exercise forearm occlusion (PEFO).Findings :1. MSNA increased in relation to the duration of handgrip exercise time and reached its maximal level at the onset of fatigue. During PEFO the MSNA response was greater than observed in the resting, pre-exercise control level.2. The MSNA response at the onset of fatigue was increased post-training compared to pre-training, while the MSNA response to PEFO was unchanged post-training.3. After four weeks detraining, the MSNA response at the onset of fatigue decreased compared to the immediate post-training and responses and the magnitude of the detraining responses remained unchanged for up to one year The MSNA response to PEFO was unchanged by training. In conclusion, although central command and muscle reflex are factors that can enhance MSNA during muscle contraction, the muscle metaboreflex-induced increase in the MSNA response to PEFO was not modulated by resistance training. On the other hand, resistance training increased central command and this effect enhanced the MSNA response transiently.