Background: A growing number of people are affected by persistent symptoms following Covid-19, defined as Long Covid. The pathophysiology of Long Covid remains unclear, including respiratory muscle dysfunction, dysautonomia, and vagal nerve dysfunction. Respiratory muscle training (RMT) has been shown to improve vascular tone, reduce symptoms of dyspnea, and improve ANS balance.

Aim: We conducted a completely remote study to investigate the effect of RMT to improve symptoms and QoL in post-Covid patients. 

Methods: More than 2000 people who had tested positive for SARS-CoV2 were enrolled. Participants received either an RMT device (The Breather) or a SHAM device, and were allocated to either control, endurance, or strength training group. All participants were asked to complete 4 weeks of cRMT using the smartphone-based Breather Coach app. Baseline, midpoint and final assessments included maximum phonation time (MPT), sit-to-stand test (STS), health-related QoL and mental wellbeing surveys. 

Results: Preliminary results reveal that 75% still had persistent symptoms at baseline. A total of 330 participants (mean age: 53) completed baseline and midpoint assessments. Midpoint assessments showed a significant main effect of time regardless of group for difficulty of breathing (p:0.007), sleep (p:0.003), activity level (p:0.013), happiness (p<0.001), energy level (p<0.001), STS (p:0.002), MPT (p:0.030).

Conclusion: The findings show that cRMT can alleviate symptoms and burden of Long Covid, and confirm feasibility and effectiveness of home-based rehabilitation in this population. Final results of the study will be discussed in combination with those of a follow-up study.