Impact of Inspiratory Muscle Training in Individuals with Gastroesophageal Reflux Disease: A Randomized Controlled Trial Protocol

Gastroesophageal reflux disease (GERD) is a common chronic condition mainly caused by the dysfunction of the antireflux mechanism at the gastroesophageal junction. This is composed of the lower esophageal sphincter and the crural diaphragm. Increasing evidence suggests that diaphragmatic dysfunction and reduced inspiratory muscle strength may contribute to the persistence of GERD symptoms. Although respiratory physiotherapy has shown beneficial effects, the role of a structured inspiratory muscle training (IMT) program has not been sufficiently examined. This study aims to investigate the effects of an inspiratory muscle training program on inspiratory muscle strength and secondary clinical outcomes in individuals with GERD. A total of thirty adults with a confirmed GERD diagnosis will be enrolled in a two-arm randomized controlled trial. These volunteers will be randomly assigned either to the experimental group, which will undergo a 3-month inspiratory muscle training (IMT) using tapered flow resistive loading at 40% of maximal inspiratory pressure (MIP), or to the control group, which will receive sham IMT with a consistent low resistance. Primary outcomes will include maximal inspiratory pressure (MIP) and maximal dynamic inspiratory pressure (S-index). Secondary outcomes will assess GERD symptoms, disease-related quality of life, and pulmonary function. Measurements will be performed at baseline, at three months of intervention, and at six months from recruitment (follow-up). IMT is expected to lead to significant improvements in inspiratory muscle strength, symptom burden, and quality of life compared with sham training. This trial will provide novel evidence regarding the role of inspiratory muscle training as a non-pharmacological intervention in the management of GERD. Trial registration: ClinicalTrials.gov Identifier: NCT07131397.