Inspiratory muscle training improves aerobic capacity, respiratory strength and quality of life in post-COVID-19 patients

<bold>Aim:</bold> To evaluate the efficacy of inspiratory muscle training (IMT) in post-COVID-19 individuals to improve submaximal aerobic capacity, respiratory muscle strength and quality of life. <bold>Material and Methods:</bold> Randomized clinical trial with 2 groups: a) IMT group using Power Breathe^® device (n=10- mean age 46.60+12.84, post COVID time 35.63+1.35 months), 8 weeks of IMT at 75% of maximal inspiratory pressure, and b) sham group (n=9 mean age 57.11+15.66 post COVID time 35.46+0,39 months): IMT without load, for the same period as the intervention group. Before and after the eight weeks, the groups underwent an assessment of inspiratory muscle strength (Incremental Respiratory Endurance Test), 6-minute walk test, spirometry and quality of life (SF-36). <bold>Results:</bold> The IMT group showed an increase in inspiratory muscle strength post-intervention (68.10±24.38 cmH2O vs. 125.5±27.68 cmH2O; Cohen's d =0.74,p<0.001), in FEV1 (74±16.22 vs. 93.5±21.73; Cohen's d =0.45, p =0.020), in the distance covered in the 6-minute walk test (463.30±74.32 m vs. 551.70 ± 69.25 m; Cohen's d = 0.52, p<0.001), in the overall SF-36 score (312.50±108.05 vs. 519.70 ± 161.94; Cohen's d = 0.60, p = 0.021), in PSQI score (9.7±2.4 vs. 4.4±3.1; Cohen's d = 0.69, p<0.001), and ESS score (11.40 ± 4 vs. 6 ± 4; Cohen's d = 0.55, p = 0.007). No differences were observed in the variables for the control group post-training. <bold>Conclusion:</bold> IMT promotes significant changes in respiratory muscle strength, lung function, and submaximal aerobic capacity and improves quality of life. IMT can be considered as an adjunct therapy for post-COVID-19 patients