Álvarez-Herms Jesús, Julià-Sánchez Sonia, Corbi Francisco, Odriozola-Martínez Adrian, Burtscher Martin
Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
National Institute of Physical Education of Catalonia (INEFC) - Lleida Centre, University of Lleida, Lleida, Spain.
Front Physiol. 2019 Jan 15;9:1970. doi: 10.3389/fphys.2018.01970. eCollection 2018.
Respiratory/inspiratory muscle training (RMT/IMT) has been proposed to improve the endurance performance of athletes in normoxia. In recent years, due to the increased use of hypoxic training method among athletes, the RMT applicability has also been tested as a method to minimize adverse effects since hyperventilation may cause respiratory muscle fatigue during prolonged exercise in hypoxia. We performed a review in order to determine factors potentially affecting the change in endurance performance in hypoxia after RMT in healthy subjects. A comprehensive search was done in the electronic databases MEDLINE and Google Scholar including keywords: "RMT/IMT," and/or "endurance performance," and/or "altitude" and/or "hypoxia." Seven appropriate studies were found until April 2018. Analysis of the studies showed that two RMT methods were used in the protocols: respiratory muscle endurance (RME) (isocapnic hyperpnea: commonly 10-30', 3-5 d/week) in three of the seven studies, and respiratory muscle strength (RMS) (Powerbreathe device: commonly 2 × 30 reps at 50% MIP (maximal inspiratory pressure), 5-7 d/week) in the remaining four studies. The duration of the protocols ranged from 4 to 8 weeks, and it was found in synthesis that during exercise in hypoxia, RMT promoted (1) reduced respiratory muscle fatigue, (2) delayed respiratory muscle metaboreflex activation, (3) better maintenance of SaO and blood flow to locomotor muscles. In general, no increases of maximal oxygen uptake (VO) were described. Ventilatory function improvements (maximal inspiratory pressure) achieved by using RMT fostered the capacity to adapt to hypoxia and minimized the impact of respiratory stress during the acclimatization stage in comparison with placebo/sham. In conclusion, RMT was found to elicit general positive effects mainly on respiratory efficiency and breathing patterns, lower dyspneic perceptions and improved physical performance in conditions of hypoxia. Thus, this method is recommended to be used as a pre-exposure tool for strengthening respiratory muscles and minimizing the adverse effects caused by hypoxia related hyperventilation. Future studies will assess these effects in elite athletes.
呼吸/吸气肌训练（RMT/IMT）已被提议用于提高常氧环境下运动员的耐力表现。近年来，由于运动员中低氧训练方法的使用增加，RMT作为一种将不良反应降至最低的方法也得到了测试，因为在低氧环境下长时间运动期间过度通气可能会导致呼吸肌疲劳。我们进行了一项综述，以确定可能影响健康受试者在进行RMT后低氧耐力表现变化的因素。在电子数据库MEDLINE和谷歌学术中进行了全面搜索，关键词包括：“RMT/IMT”、和/或“耐力表现”、和/或“海拔”和/或“低氧”。截至2018年4月，共找到七项合适的研究。对这些研究的分析表明，实验方案中使用了两种RMT方法：七项研究中的三项采用呼吸肌耐力（RME）（等碳酸过度通气：通常10 - 30分钟，每周3 - 5天），其余四项研究采用呼吸肌力量（RMS）（Powerbreathe装置：通常在50%最大吸气压（MIP）下进行2×30次重复，每周5 - 7天）。实验方案的持续时间为4至8周，综合研究发现，在低氧运动期间，RMT促进了：（1）呼吸肌疲劳减轻；（2）呼吸肌代谢性反射激活延迟；（3）更好地维持动脉血氧饱和度（SaO）和运动肌肉的血流。一般来说，未描述最大摄氧量（VO）增加。与安慰剂/假干预相比，使用RMT实现的通气功能改善（最大吸气压）增强了适应低氧的能力，并在适应阶段将呼吸应激的影响降至最低。总之，发现RMT主要对呼吸效率和呼吸模式产生总体积极影响，降低呼吸困难感，并改善低氧条件下的身体表现。因此，建议将该方法用作增强呼吸肌和将低氧相关过度通气引起的不良反应降至最低的预暴露工具。未来的研究将评估这些影响在精英运动员中的情况。
