Effects of inspiratory muscle training on autonomic control: systematic review

ABSTRACT The autonomic nervous system dysfunction has an important role on the physiopathology of some diseases. A possible option to improve the autonomic control is the inspiratory muscle training (IMT). The aim of this study was to systematically review the available literature about the effects of this training modality on autonomic control. A search was performed for controlled and randomized clinical trials on database MEDLINE, PEDro, SciELO and LILACS by two independent reviewers, who also evaluated the methodologic quality (PEDro scale). 181 articles were found and, after elegibility criteria analysis, four studies were included. The included studies showed good methodological quality and assessed the effect of IMT on the autonomic control of participants with risk factors for cardiovascular disease. The autonomic control was evaluated by heart rate variability (HRV) analysis and by noradrenaline plasma levels. The IMT improved autonomic control in 3 studies, reducing the sympathetic nervous system (noradrenaline plasma levels; LF nu - HRV) and increasing the vagal nervous system (HF un - HRV). It is concluded that IMT may be a therapeutic alternative to improve the autonomic control.

摘要 自主神经系统（autonomic nervous system）功能异常在部分疾病的病理生理进程中发挥重要作用。改善自主神经调控的可行方案之一为吸气肌训练（inspiratory muscle training, IMT）。本研究旨在系统综述该训练模式对自主神经调控影响的现有文献。两名独立评价者在MEDLINE、PEDro、SciELO及LILACS数据库中检索对照及随机对照临床试验，并采用PEDro量表（PEDro scale）评价研究的方法学质量。初检共获取181篇文献，经纳入排除标准分析后，最终纳入4项研究。纳入的研究均具备良好的方法学质量，且针对存在心血管疾病危险因素的受试者，评估了吸气肌训练对其自主神经调控的影响。自主神经调控通过心率变异性（heart rate variability, HRV）分析及血浆去甲肾上腺素水平进行评估。结果显示，3项研究表明吸气肌训练可改善自主神经调控：降低交感神经系统活性（血浆去甲肾上腺素水平；低频归一化单位-心率变异性，LF nu - HRV），并提升迷走神经系统活性（高频归一化单位-心率变异性，HF nu - HRV）。综上，吸气肌训练或可作为改善自主神经调控的治疗选择。