Effectiveness of different protocols and loads used in inspiratory muscle training of individuals with COPD: a systematic review

ABSTRACT Chronic obstructive pulmonary disease (COPD) changes the musculoskeletal system, including the respiratory muscles, which are responsible for increasing dyspnea and reducing functional capacity. Several studies have already showed the effectiveness of inspiratory muscle training (IMT); therefore, it should be part of the pulmonary rehabilitation program. However, assessing the best way to do it is still necessary. Thus, this study aimed to evaluate, by a systematic review, the effectiveness of different IMT protocols and loads on the outcomes of inspiratory muscle strength and endurance, functional capacity, and dyspnea reduction. This systematic review was performed in accordance with the PRISMA protocol. Studies were searched in February 2021 in the PubMed, SciELO, PEDro. For the search, the following keywords were used: “COPD” and “breathing exercises, resistive training, respiratory muscle training.” A total of 398 individuals previously diagnosed with COPD were included in the 10 selected studies. Different IMT devices were used and protocols varied in relation to loads and progression. Threshold was the most used IMT device. Its load was established according to the percentage of maximal inspiratory pressure (MIP) (30-80%) and readjusted according to new measurements taken every one or two weeks. Respiratory muscle training with both low loads and high loads presented positive results, however, establishing which is the best IMT protocol for individuals with COPD is not possible yet. Inspiratory muscle strength, functional capacity, and dyspnea get better with IMT.