Inspiratory muscle training and aerobic exercise for respiratory muscle strength in myasthenia gravis post-hospitalization- a randomized controlled trial

Background: Previous studies have demonstrated the positive effects of long-term inspiratory muscle training (IMT) on inspiratory muscle strength and pulmonary function. However, the benefits of IMT with aerobic exercise (IMT + AE) in patients with myasthenia gravis (MG) remain unclear. This randomized controlled trial aimed to assess the impact of the early, 6-week, moderate-intensity interval IMT + AE on pulmonary function, functional capacity, and respiratory muscle strength in patients with MG post-hospitalization. Methods: Patients with Discharged MG were randomly assigned to either a control group receiving standard medical management or an intervention group undergoing six-week IMT + AE program. Respiratory status was evaluated using the maximum inspiratory/expiratory pressure (MIP/MEP) and pulmonary function tests. Modified Borg dyspnea scores and a six-minute walk test for functional capacity were also employed. Results: Fifty-four participants were assigned to either the control (sixn = 28) or IMT + AE groups (n = 26). At 6 weeks, the IMT + AE group showed significant improvements across all parameters, while the control group only showed notable differences in the modified Borg scale scores and walking distance. MIP improvements were 33.8 ± 36.1 cmH₂O in IMT and 22.1 ± 25.8 cmH₂O in control groups (P = 0.18). The IMT + AE group improvements were more substantial in MEP, modified Borg scale, and 6-minute walk distance, in addition to forced vital capacity (FVC) and FVC % of prediction (0.21 ± 0.24 L and 6.17 ± 6.01%, respectively), while the control group showed decreased volumes (-0.06 ± 0.30 L and − 1.79 ± 9.69%, respectively). FVC improvement was significant with IMT + AE (0.21 ± 0.24 L) vs. reduction in the control group (-0.06 ± 0.3 L; P = 0.001). Conclusions: Implementing six-week moderate-intensity interval IMT + AE effectively enhanced respiratory muscle strength, alleviated dyspnea, improved physical capacity, and increased FVC in patients with MG following hospitalization after discharge. Clinical trial registration: The study was registered in The Clinical Trials Clinical Trial (NCT06624345||https://www.clinicaltrials.gov/) on October 12, 2024 (retrospectively registered).