BACKGROUND: Inspiratory and expiratory muscle training (RMT) has been shown to have beneficial effects in individuals with long-term post-COVID-19 symptoms.
OBJECTIVE: To assess the effects of adding RMT to an aerobic exercise (AE) training program for health-related quality of life (HRQoL) and exercise tolerance in individuals with long-term post-COVID-19 symptoms, and to evaluate the effects on physical and lung function, and psychological status.
METHODS: 64 individuals with long-term post-COVID-19 symptoms of fatigue and dyspnoea were randomly assigned to AE+RMT or AE+RMTgroups for an 8-wk intervention (AE: 50min/day, 2 times/wk; RMT: 40min/day, 3 times/wk). Primary outcomes were HRQoL (EuroQol-5D questionnaire) and exercise tolerance (cardiopulmonary exercise test). Secondary outcomes were physical function: respiratory muscle function (inspiratory/expiratory muscle strength and inspiratory muscle endurance), lower and upper limb strength (1-min Sit-to-Stand and handgrip force); lung function: spirometry testing and lung diffusing capacity; and psychological status (anxiety/depressive levels). sham
RESULTS: Postintervention, there were no statistically significant improvements in HRQoL or exercise tolerance in the AE+RMT compared with the AE+RMTgroup. In the AE+RMT group, large improvements in respiratory muscle function (d = 0.7 to 1.3) and low-moderate improvements in peak expiratory flow (d = 0.4) occurred compared with the AE+RMTgroup. Lung function outcomes, lower and upper limb strength and psychological status did not increase more in the AE+RMT group than in the AE+RMTgroup. sham sham sham
CONCLUSION: For individuals with long-term post-COVID-19 symptoms, combining RMT with an AE training program resulted in improvements in respiratory muscle strength, inspiratory muscle endurance and peak expiratory flow; however, the differences between groups were not statistically significant for HRQoL, exercise tolerance, psychological distress, and lung diffusing capacity.
DATABASE REGISTRATION: United States Clinical Trials Registry (NCT05597774).
