Late Breaking Abstract - A randomised control trial using inspiratory muscle training in post-COVID-19 rehabilitation

Introduction: One in ten people recovering from COVID-19 experience prolonged symptoms (>12 weeks), with many reporting breathlessness more than a year after acute infection. There is an urgent need to understand the recovery from COVID-19 and to identify safe, effective rehabilitative strategies.

Aims: To investigate the recovery from COVID-19 and the potential rehabilitative role of inspiratory muscle training (IMT).

Methods: 250 adults (48±16 yrs; 84% female) recovering from self-reported COVID-19, with a primary symptom of shortness of breath, were randomised 4:1 to an 8-week IMT or control arm, respectively. Breathlessness (King’s Brief Interstitial Lung Disease (KBILD) Questionnaire), respiratory muscle strength, fitness (Chester Step Test) and device-based physical activity (PA) were assessed at baseline and post-intervention.

Results: In the first 87 participants (68 IMT) completed to date, IMT improved all domains of the KBILD, with breathlessness reduced by 33% (P<.001) - twice the minimal clinically important difference. Furthermore, IMT improved maximal inspiratory pressure (MIP; baseline 75±32 vs. post 117±58 cmH2O; P<.001), sustained MIP (420±204 vs. 575±265 PTUs; P<.001), fatigue index (17±12 vs. 23±16 au; P<.001) and fitness (36±13 vs. 44±19 ml·kg-1·min-1; P<.001). PA was unchanged. Time was associated with non-significant improvements in all parameters, but the magnitude of improvement was 2–14 times greater with IMT.

Conclusions: IMT significantly accelerated the rate of recovery from COVID-19 and represents an acceptable and feasible home-based rehabilitation tool that should be considered for wider implementation as part of COVID-19 recovery strategies.