Inspiratory Muscle Training in Chronic Obstructive Pulmonary Disease Patients: A Scoping Review

Introduction: COPD is a leading cause of chronic disease and death globally, with high mortality rates for those hospitalized or requiring mechanical ventilation. Delaying disease progression and improving patient outcomes can reduce healthcare costs and societal impact. Respiratory muscles play a crucial role in COPD, and specific endurance respiratory exercises have been shown to improve muscle fibers and mitochondrial activity, reducing oxidative stress and fatigue. Inspiratory Muscle Training (IMT) is a recommended pulmonary rehabilitation technique that enhances lung capacity and improves exercise performance by altering muscle fiber types and distribution. The impact of IMT implemented in COPD remains unclear. This scoping review aims to ascertain the impact IMT has on COPD patients. Methods: A scoping review was performed in PubMed, Academic Search Complete/EBCSCO, and Grey Literature sources, including Google Scholar. IMT studies evaluating interventions for COPD patients that were published in 2018-2023 were included. Results: We reviewed 644 studies, nine IMT interventions met inclusion criteria and were included in the current study. In the majority of studies, improvements were noted through the implementation of IMT interventions. Several facilitators and barriers were noted during implementation and contributed to the success or failure of the intervention. Conclusion: Overall, IMT had conflicting effects on a variety of COPD patient outcomes. Numerous studies demonstrate, however, that IMT can improve COPD-related outcomes, such as respiratory muscle function, dyspnea symptoms, quality of life, autonomic function, exercise tolerance, diaphragmatic strength and reduced exertional dyspnea, and balance.