Martins de Abreu Raphael, Porta Alberto, Rehder-Santos Patricia, Cairo Beatrice, Donisete da Silva Claudio, De Favari Signini Étore, Sakaguchi Camila Akemi, Catai Aparecida Maria
Department of Physical Therapy, Federal University of São Carlos, São Carlos, São Paulo, Brazil.
Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
Am J Physiol Regul Integr Comp Physiol. 2019 Dec 1;317(6):R891-R902. doi: 10.1152/ajpregu.00167.2019. Epub 2019 Oct 9.
Chronic effects of inspiratory muscle training (IMT) on autonomic function and baroreflex regulation are poorly studied. This study aims at evaluating chronic effects of different IMT intensities on cardiovascular control in amateur cyclists. A longitudinal, randomized, controlled blind study was performed on 30 recreational male cyclists undergoing IMT for 11 wk. Participants were randomly allocated into sham-trained group (SHAM, = 9), trained group at 60% of the maximal inspiratory pressure (MIP60, = 10), and trained group at critical inspiratory pressure (CIP, = 11). Electrocardiogram, finger arterial pressure, and respiratory movements were recorded before (PRE) and after (POST) training at rest in supine position (REST) and during active standing (STAND). From the beat-to-beat series of heart period (HP) and systolic arterial pressure (SAP), we computed time domain markers, frequency domain indexes in the low frequency (0.04-0.15 Hz) and high frequency (HF, 0.15-0.4 Hz) bands, an entropy-based complexity index (CI), and baroreflex markers estimated from spontaneous HP-SAP sequences. Compared with SHAM, the positive effect of MIP60 over the HP series led to the HF power increase during REST (PRE: 521.2 ± 447.5 ms; POST: 1,161 ± 878.9 ms) and the CI rise during STAND (PRE: 0.82 ± 0.18; POST: 0.97 ± 0.13). Conversely, the negative effect of CIP took the form of the decreased HP mean during STAND (PRE: 791 ± 71 ms; POST: 737 ± 95 ms). No effect of IMT was visible over SAP and baroreflex markers. These findings suggest that moderate-intensity IMT might be beneficial when the goal is to limit cardiac sympathetic hyperactivity at REST and/or in response to STAND.
吸气肌训练(IMT)对自主神经功能和压力反射调节的慢性影响研究较少。本研究旨在评估不同强度的IMT对业余自行车运动员心血管控制的慢性影响。对30名接受11周IMT训练的男性休闲自行车运动员进行了一项纵向、随机、对照盲法研究。参与者被随机分为假训练组(SHAM,n = 9)、最大吸气压力60%训练组(MIP60,n = 10)和临界吸气压力训练组(CIP,n = 11)。在仰卧位休息(REST)和主动站立(STAND)时,于训练前(PRE)和训练后(POST)记录心电图、手指动脉压和呼吸运动。从逐搏的心动周期(HP)和收缩期动脉压(SAP)系列中,我们计算了时域指标、低频(0.04 - 0.15 Hz)和高频(HF,0.15 - 0.4 Hz)频段的频域指数、基于熵的复杂度指数(CI)以及从自发的HP - SAP序列估计的压力反射指标。与SHAM组相比,MIP60对HP系列的积极影响导致REST期间HF功率增加(PRE:521.2±447.5毫秒;POST:1161±878.9毫秒)以及STAND期间CI升高(PRE:0.82±0.18;POST:0.97±0.13)。相反,CIP的负面影响表现为STAND期间HP平均值降低(PRE:791±71毫秒;POST:737±95毫秒)。IMT对SAP和压力反射指标没有明显影响。这些发现表明,当目标是在休息时和/或对站立做出反应时限制心脏交感神经活动过度时,中等强度的IMT可能有益。