Comparison of the Effects of High-Intensity and Low-Intensity Inspiratory Muscle Training in Individuals With Multiple Sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system. Although the pathogenesis of the disease is not fully understood, genetic and environmental factors are thought to contribute to its development. Demyelinating plaques, the primary pathological hallmark of MS, are most commonly found in the optic nerves, brainstem, spinal cord, and periventricular white matter. The clinical manifestations of the disease vary depending on the regions of the central nervous system affected and the extent of inflammation and axonal demyelination. Respiratory function and respiratory muscle strength have been shown to be lower in individuals with MS compared with healthy individuals. The risk of death due to respiratory complications is approximately 12 times higher in the MS population than in the general population, and 47% of MS-related deaths are attributed to respiratory complications. These findings highlight the critical importance of early interventions targeting respiratory function.

Although inspiratory muscle training (IMT) has been shown to improve respiratory function, its effects on functional outcomes in individuals with MS have not been sufficiently investigated. However, these functional outcomes are important for improving quality of life and optimizing rehabilitation in individuals with MS. Furthermore, because studies investigating IMT in individuals with MS are limited, the optimal training protocol in terms of training frequency, intensity, and duration has not yet been clearly established. Recent studies have demonstrated that high-intensity interval IMT is effective in improving respiratory function, respiratory muscle strength, and functional capacity in individuals with chronic obstructive pulmonary disease, bronchiectasis, and heart failure, and that it is well tolerated by patients. To the best of our knowledge, no study has investigated the effects of this approach in individuals with MS.

This study is designed as a randomized controlled trial. A total of 48 individuals diagnosed with MS will be randomly assigned to one of three groups: high-intensity interval IMT, low-intensity IMT, or conventional rehabilitation. The intervention period will last 8 weeks. All three groups will receive conventional rehabilitation consisting of aerobic and resistance exercises. In addition, the IMT groups will receive either high-intensity interval IMT or low-intensity IMT. The primary outcome measures of the study are respiratory muscle strength, pulmonary function, and cough strength. Secondary outcome measures include exercise capacity, lower extremity functional muscle strength, balance, fatigue, dysphagia severity, sleep quality, and quality of life.