E3 PreliminaryPreliminaryPEM unclearObservationalPeer-reviewedReviewed
A Pilot Study on the Effects of Exercise Training on Cardiorespiratory Performance, Quality of Life, and Immunologic Variables in Long COVID.
Abbasi, Asghar, Gattoni, Chiara, Iacovino, Michelina et al. · Journal of clinical medicine · 2024 · DOI
Quick Summary
This study tested whether supervised aerobic exercise training could help people with long COVID. Fourteen participants completed 20 sessions of exercise training over 10 weeks. After training, people reported feeling less fatigued, less anxious and depressed, and had better heart and lung fitness—without experiencing harmful immune system changes.
Why It Matters
Exercise intolerance and post-exertional malaise are defining features of ME/CFS and long COVID. This study provides preliminary evidence that carefully designed aerobic training can improve fitness and quality of life without triggering immune dysregulation or exacerbating symptoms, which has important implications for rehabilitation protocols in post-viral fatigue conditions.
Observed Findings
- Peak work rate increased significantly by 16 watts (p=0.010) after training.
- VO₂peak improved by 1.55 mL/kg/min (p=0.030), indicating better cardiorespiratory fitness.
- Patient-reported fatigue severity decreased by 11%, depression by 42%, and anxiety by 29%.
- Dyspnea (shortness of breath) improved by 46%.
- Circulating immune cell counts and plasma inflammatory cytokine concentrations remained normal and unchanged with training.
Inferred Conclusions
- Aerobic endurance exercise training improves cardiorespiratory fitness and reduces symptom severity in long COVID patients.
- Exercise-induced improvements in mental health (anxiety, depression) can occur without evidence of immune system harm.
- Baseline inflammatory markers in this long COVID cohort remained normal; exercise training did not trigger or exacerbate systemic inflammation.
Remaining Questions
- Does exercise training benefit or harm long COVID patients with more severe post-exertional malaise, and how should PEM be systematically assessed and prevented?
- Why did 6-minute walk distance and overall physical activity not improve despite increased VO₂peak and work capacity?
What This Study Does Not Prove
This pilot study does not prove exercise training is safe or effective for all ME/CFS or long COVID patients, particularly those with severe post-exertional malaise—the study did not systematically assess or define PEM outcomes. The small sample size (n=14) and lack of control group mean findings cannot establish causation or generalize to broader populations. Normal baseline inflammatory markers in this cohort may not reflect immune dysfunction in more severely affected patients.
Tags
Symptom:Post-Exertional MalaiseFatigue
Biomarker:CytokinesBlood Biomarker
Phenotype:Infection-TriggeredLong COVID Overlap
Method Flag:PEM Not DefinedWeak Case DefinitionNo ControlsSmall SampleExploratory Only
Metadata
- DOI
- 10.3390/jcm13185590
- PMID
- 39337079
- 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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