E3 PreliminaryPreliminaryPEM unclearPeer-reviewedReviewed
Inspiratory muscle training improves autonomic function in myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of SARS-CoV-2: A pilot study.
Edgell, Heather, Pereira, Tania J, Kerr, Kathleen et al. · Respiratory physiology & neurobiology · 2025 · DOI
Quick Summary
This study tested whether a simple breathing exercise program could help people with ME/CFS and Long COVID feel better. For 8 weeks, participants practiced strengthening their breathing muscles. People in all groups—including those with ME/CFS and Long COVID—showed improvements in how far they could walk, their heart rate, sleep quality, and how their nervous system functioned. Those with ME/CFS also noticed less pain and better blood vessel function.
Why It Matters
This study addresses a critical gap in ME/CFS treatment by testing a simple, low-risk intervention targeting autonomic nervous system dysfunction—a hallmark feature of the disease. The convergence of benefits in both ME/CFS and Long COVID suggests IMT may address shared pathophysiological mechanisms. Given the scarcity of evidence-based treatments for these conditions, identifying safe, accessible interventions is essential.
Observed Findings
- All participants showed significant improvements in inspiratory muscle strength (p<0.001) and 6-minute walk distance (p=0.002) after 8 weeks of IMT.
- Resting heart rate decreased and heart rate variability improved across all groups (p=0.037 and p<0.05, respectively).
- Sleep-related symptoms improved in all groups (p=0.009).
- In ME/CFS participants specifically, vascular function improved (p=0.001) and pain symptoms decreased (p=0.016).
- ME/CFS participants showed improved secretomotor function and total autonomic symptom burden on COMPASS 31 questionnaire (p=0.023 and p=0.005).
Inferred Conclusions
- Eight weeks of inspiratory muscle training can improve autonomic nervous system function and exercise capacity in people with ME/CFS and Long COVID.
- Autonomic improvements are measurable through both objective measures (heart rate variability, vascular function) and patient-reported symptoms (pain, sleep).
- IMT may be a safe, accessible intervention for managing autonomic dysfunction in post-viral conditions.
Remaining Questions
- What is the optimal duration and intensity of IMT for different ME/CFS severity levels?
- Do improvements persist beyond 8 weeks, or is ongoing training required for sustained benefits?
What This Study Does Not Prove
This pilot study does not establish IMT as an effective standard treatment for ME/CFS, as it lacks a randomized control design and has a small sample size. The study does not prove causation—improvements in heart rate variability and other measures may reflect placebo effects, natural recovery, or confounding factors. Longer-term effects and optimal training protocols remain unknown.
Tags
Symptom:Unrefreshing SleepOrthostatic IntolerancePainFatigue
Biomarker:Blood Biomarker
Phenotype:Infection-TriggeredLong COVID Overlap
Method Flag:PEM Not DefinedSmall SampleExploratory OnlyMixed Cohort
Metadata
- DOI
- 10.1016/j.resp.2024.104360
- PMID
- 39374820
- Review status
- Editor reviewed
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- Last updated
- 12 April 2026
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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