New Study: ME/CFS and Long COVID Share Similar Exercise Impairments: Largest iCPET Cohort Shows Preload Failure and O₂ Extraction Issues

(2025) American Journal of Respiratory and Critical Care Medicine: 'Exercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome & Long COVID: Commonalities Detected by Invasive Cardiopulmonary Exercise Testing’ https://www.atsjournals.org/doi/abs/10.1164/ajrccm.2025.211.Abstracts.A7881By David Systrom et al.

Conclusions: 'We report the largest cohort of ME/CFS and LC investigated with iCPET to date. ME/CFS and LC share symptomatic, reduced aerobic capacity at peak exercise, which is driven by preload insufficiency and impaired systemic O2 extraction, the latter compatible with peripheral left-to-right shunting and/or limb skeletal muscle dysfunction. These findings should drive future diagnostics and personalized medicine in both diseases. We hope these data inform the pending prospective NIH RECOVER iCPET study of LC.’