Resistive Respiratory Muscle Training Increases Respiratory Muscle Strength and Exercise Endurance, and Reduces Fatigue in MS
Objectives: The objective of this study was to determine the effects of 6 weeks of RRMT on respiratory muscle strength, exercise endurance and fatigue in MS patients with mild-to-moderate disability.
Methods: Twenty-one female and 8 male MS patients were randomly assigned to RRMT (13 women, 1 man) or placebo Control (8 women, 7 men) groups. All patients had EDSS scores between 1.0 and 6.0, and were able to pedal a cycle ergometer continuously for 10 minutes. They were nonsmokers, had not had a relapse or new steroid use in the last 6 weeks or had a recent respiratory infection. Ages were 51.1±13.3 years (RRMT) and 48.6±12.8 years (C). Average EDSS scores were 3.1±1.9 (RRMT) and 2.9±1.8 (C). Average years since diagnosis were 12.5±7.0 (RRMT) and 15.4±11.6 (C). The measurements of maximal inspiratory (PImax) and expiratory (PEmax) pressures (Viasys metabolic system) and self-reported fatigue (Modified Fatigue Impact Scale, MFIS), as well as exercise time to voluntary exhaustion at 60% of peak workload on a cycle ergometer were conducted before and after 6 weeks of the intervention. The RRMT and placebo control (no load) breathing were conducted 3 times/week, 30 minutes per session using a specially designed device that measured inspiratory and expiratory pressures on each breath. Resistances for RRMT progressively increased from 30-80% of the initial maximal inspiratory and expiratory pressures over the 6 weeks. The patients completed one session in the lab and then two sessions at home each week. T-tests were used to analyze the changes from before to after the intervention.
Results: The RRMT group had significant improvements in PImax (p=.0037; 77.3±31.2 to 97.5±28.0 cmH2O), PEmax (p=.0020; 74.6±22.5 to 97.6±25.6 cmH2O), MFIS physical fatigue (p=.0022; 16.6±8.8 to 12.5±7.2), MFIS total fatigue (p=.0125; 33.7±15.4 to 26.2±16.4), and exercise duration (p=.0295; 24.2±15.4 to 31.7±25.5 minutes) from pre to post-intervention. The placebo control group did not have significant changes in any of the physical measures.
Conclusions: A 6-week resistive respiratory muscle training program of the inspiratory and expiratory muscles improves respiratory muscle strength, exercise endurance and perceived fatigue in MS patients with mild-to-moderate disability.
This study was funded by NIDRR grant H133G120081.