Cardiopulmonary Exercise Testing Reveals Functional Limitations and Work Disability in Severe Post-COVID-19 and ME/CFS Patients

BACKGROUND: Patients severely affected by post-COVID-19 condition (PCC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) often experience long-term work incapacity, contributing to a growing economic burden. Organ-centered clinical diagnostics frequently fail to explain their work disability. OBJECTIVES: pulse [mL/bpm]) is reduced in ME/CFS, independent of comorbidity. METHODS: The study was conducted in the Department of Sports Medicine, Prevention and Rehabilitation at Johannes Gutenberg-University Mainz (Mainz, Germany). Between July 31, 2023, and March 31, 2025, a total of 92 PCC patients with suspected occupational disease underwent symptom-limited CPET and completed the Canadian Consensus Criteria, Bell Disability Scale (Bell-Score), and DePaul Symptom Questionnaire (Post-Exertional Malaise) Short Form (DSQ-PEM). RESULTS: and PPO significantly correlated with Bell-Score (r = 0.3, p = 0.005 and r = 0.3, p = 0.003) and were the lowest among patients on medical sick leave (13.3 ± 3.3 and 0.9 ± 0.3), compared to those in occupational reintegration (16.0 ± 3.9, p = 0.04 and 1.2 ± 0.5, p = 0.024) or currently working (18.0 ± 7.1, p = 0.036 and 1.2 ± 0.5, p = 0.015). CONCLUSIONS: and PPO are associated with subjective disability and occupational status. Therefore, early integration of CPET into clinical and occupational evaluations can inform individualized therapy planning and return-to-work decisions. Trial registration DRKS, DRKS00032394. Registered 28 July 2023, https://drks.de/search/de/trial/DRKS00032394.