Respiratory Rehabilitation After COVID-19: Efficacy of Inspiratory Muscle Training on Lung Function, Quality of Life and Sleep Quality: A Randomized Clinical Trial

Background and Purpose: Post-COVID-19 syndrome significantly impacts respiratory function and quality of life. Inspiratory muscle training (IMT) has been proposed as a potential intervention to improve respiratory muscle strength and overall recovery. This study aimed to evaluate the effects of IMT on respiratory muscle performance, lung function, functional capacity, sleep quality, and quality of life in individuals with post-COVID-19 syndrome. Methods: Nineteen individuals with post-COVID-19 syndrome were randomized into an IMT group (N = 10) or a sham group (N = 9). The IMT group performed eight weeks of training at 50% of maximal inspiratory pressure (MIP), while the sham group used a non-load device. Outcomes included MIP (cm H2O), functional capacity (6MWT), lung function (spirometry), sleep quality (PSQI), and quality of life (SF-36). Results: The IMT group showed significant improvements in MIP (125.50 ± 22.50 vs. 93.67 ± 20.87 cm H2O; p = 0.036; Cohen’s d = 0.50), PSQI (4.40 ± 2.50 vs. 9.00 ± 2.80; p = 0.011; Cohen’s d = 0.60), and SF-36 (p = 0.030). The IMT group also increased 6MWT distance by 58.36 ± 25.10 m. Conclusions: IMT significantly improved respiratory muscle strength, sleep quality, and quality of life in post-COVID-19 syndrome. These findings suggest that IMT may be an effective intervention, warranting further studies to confirm long-term benefits.