A Study on the Impact of Six Weeks of High-Intensity Inspiratory Muscle Training on the Prognosis of Patients With Myasthenia Gravis

Abstract

Background:

The effect of moderate to high-intensity inspiratory muscle training (IMT) on patients with myasthenia gravis remains uncertain. This study explored the effect of 6-week moderate to high-intensity IMT on the respiratory muscle strength, lung functions, dyspnea, and exercise capacity of patients with myasthenia gravis.

Methods:

A randomized controlled trial was conducted, in which patients were randomly assigned to the IMT group (n = 26) and the non-IMT group (n = 28). While the non-IMT group did not receive interventional training, the IMT group completed an IMT program that entailed 2 training sessions per day for 6 weeks, with each training session involving 30 repetitions of exercise. During the training, the resistive load started at a moderate intensity (P_Imax 40%) and increased weekly until it reached a high intensity (P_Imax 60%). The two groups were compared on their respiratory muscle strength, dyspnea, lung functions, and exercise capacity.

Results:

The IMT group scored significantly higher on the Borg dyspnea scale (1.50 ± 0.88 vs 0.82 ± 1.31, respectively, P = .032), maximum inspiratory pressure (41.15 ± 27.18 vs 18.93 ± 50.14 cm H₂O, respectively, P = .050 ), 6-min walk distance (89.50 ± 90.70 vs 25.36 ± 46.11, respectively, P = .003), forced vital capacity (0.21 ± 0.24 vs -0.06 ± 0.30, respectively, P = .001), FEV₁ (0.19 ± 0.34 vs -0.05 ± 0.28, respectively, P = .008), and vital capacity (0.61 ± 0.48 vs 0.27 ± 0.33, respectively, P = .004) than did the non-IMT group.

Conclusions:

Compared to the non-IMT group, the IMT group exhibited higher respiratory muscle strength, lung functions, and exercise capacity and less severe dyspnea after receiving the 6-week IMT.