Putative Role of Respiratory Muscle Training to Improve Endurance Performance in Hypoxia: A Review

Abstract

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 SaO2 and blood flow to locomotor muscles. In general, no increases of maximal oxygen uptake (VO2max) 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.

Effects Of Home-Based Inspiratory Muscle Training In Sickle Cell Disease (Scd) Patients

“…Especially in the respiratory muscles, IMT improves clearance ability and tolerance to the levels of lactate and hydrogen ions (38,39). Therefore, strengthening of inspiratory muscles probably attenuated the metaboreflex of inspiratory muscles, which increased blood flow and oxygenation of limb muscles, reducing premature fatigue during exercise in hypoxia (16,40,41). Nevertheless, these the results must be viewed with caution, since direct metaboreflex measurements were not performed in the present study.…”

“…Some studies in patients with COPD and asthma have also reported reduced muscle fatigue and increased exercise functional capacity after IMT (34,37). There is an increase in the level of metabolites in the circulation, such as lactate and hydrogen ions because of the increase in anaerobic metabolism induced by exercise in hypoxia (16). Especially in the respiratory muscles, IMT improves clearance ability and tolerance to the levels of lactate and hydrogen ions (38,39).…”

“…Inspiratory muscle training (IMT) has been shown to be an efficient method of improving exercise tolerance and inspiratory and expiratory muscle strength in a number of diseases (13,14). Some studies have shown that IMT even enables increased oxygen uptake in the blood, decreases the perception of dyspnea and delays the onset of premature fatigue (15,16). However, the effects of IMT in patients with sickle cell anemia are relatively unknown.…”

Revisiting pulmonary rehabilitation during COVID-19 pandemic: a narrative review

“…Requirement of mechanical ventilation with intubation may be regarded as surrogate markers for severe illness and low lung compliance [47]. In such a scenario, post COVID-19 recovery patient during respiratory muscle training (RMT) exercising with a duration of 4 to 8 weeks in hypoxia usually results in (1) decreased respiratory muscle fatigue, (2) late respiratory muscle metaboreflex activation, (3) and better maintenance of oxygen saturation (SaO 2 ) and blood flow to the active muscles [48].…”

Effect of lung function disorders and physical activity on smoking and non-smoking students

“…Physical activities have beneficial effects on the respiratory system [ 10 ], improving lung function [ 11 ] and increasing the vital capacity. Indeed, an individual who takes regular physical exercise can train the respiratory muscles, with the result that a greater volume of oxygen can enter the pulmonary capillaries, and lungs capacity increases [ 12-14 ]. Moreover, intense physical activity can reduce systemic and bronchial inflammation, improving both lung function and quality of life [ 15 ].…”