Chlif Mehdi, Chaouachi Anis, Ahmaidi Said
EA-3300 :APERE, Exercise Physiology and Rehabilitation Laboratory, Picardie Jules Verne University, Sport Sciences Department, Avenue Paul Claudel, F-80025, Amiens Cedex, France.
Tunisian Research Laboratory "Sport Performance Optimisation", National Center of Medicine and Science in Sports (CNMSS), Tunis, Tunisia.
Respir Care. 2017 Jul;62(7):936-946. doi: 10.4187/respcare.04923. Epub 2017 Apr 25.
Obese patients show a decline in exercise capacity and diverse degrees of dyspnea in association with mechanical abnormalities, increased ventilatory requirements secondary to the increased metabolic load, and a greater work of breathing. Consequently, obese patients may be particularly predisposed to the development of respiratory muscle fatigue during exercise. The aim of this study was to assess inspiratory muscle performance during incremental exercise in 19 obese male subjects (body mass index 41 ± 6 kg/m) after aerobic exercise training using the noninvasive, inspiratory muscle tension-time index (T).
Measurements performed included anthropometric parameters, lung function assessed by spirometry, rate of perceived breathlessness with the modified Borg dyspnea scale (0-10), breathing pattern, maximal exercise capacity, and inspiratory muscle performance with a breath-by-breath automated exercise metabolic system during an incremental exercise test. T was calculated using the equation, T = P/P × T/T (where P represents mouth occlusion pressure, P is maximal inspiratory pressure, and T/T is the duty cycle).
At rest, there was no statistically significant difference for spirometric parameters and cardiorespiratory parameters between pre- and post-training. At maximal exercise, the minute ventilation, the rate of exchange ratio, the rate of perceived breathlessness, and the respiratory muscle performance parameters were not significantly different pre- and post-training; in contrast, tidal volume ( = .037, effect size = 1.51), breathing frequency ( = .049, effect size = 0.97), power output ( = .048, effect size = 0.79), peak oxygen uptake ( = .02, effect size = 0.92) were significantly higher after training. At comparable work load, training induces lower minute ventilation, mouth occlusion pressure, ratio of occlusion pressure to maximal inspiratory pressure, T, and rate of perceived breathlessness.
Aerobic exercise at ventilatory threshold can induce significant improvement in respiratory muscle strength, maximal exercise capacity, and inspiratory muscle performance and decreased dyspnea perception in obese subjects.
肥胖患者表现出运动能力下降以及不同程度的呼吸困难，这与机械异常、代谢负荷增加导致通气需求增加以及呼吸功增大有关。因此，肥胖患者在运动期间可能特别容易发生呼吸肌疲劳。本研究的目的是使用无创吸气肌张力 - 时间指数（T）评估19名肥胖男性受试者（体重指数41±6kg/m²）在有氧运动训练后进行递增运动时的吸气肌表现。
所进行的测量包括人体测量参数、通过肺活量测定法评估的肺功能、使用改良的博格呼吸困难量表（0 - 10）评估的主观呼吸急促程度、呼吸模式、最大运动能力以及在递增运动试验期间使用逐次呼吸自动运动代谢系统评估的吸气肌表现。T 使用公式T = P/P × T/T 计算（其中P 代表口腔闭塞压力，P 是最大吸气压力，T/T 是占空比）。
在静息状态下，训练前后肺活量测定参数和心肺参数无统计学显著差异。在最大运动时，分钟通气量、气体交换率、主观呼吸急促程度和呼吸肌表现参数训练前后无显著差异；相比之下，训练后潮气量（P = 0.037，效应量 = 1.51）、呼吸频率（P = 0.049，效应量 = 0.97）、功率输出（P = 0.048，效应量 = 0.79）、峰值摄氧量（P = 0.02，效应量 = 0.92）显著更高。在相当的工作负荷下，训练可导致较低的分钟通气量、口腔闭塞压力、闭塞压力与最大吸气压力之比、T 和主观呼吸急促程度。
在通气阈值下进行有氧运动可使肥胖受试者的呼吸肌力量、最大运动能力和吸气肌表现得到显著改善，并降低呼吸困难的感知。
