Exercise Training Improves Symptomatology and Immune Cell Phenotype in Long COVID Patients-Preliminary Results

<bold>Aim</bold> We studied Long COVID (LC) patients without autonomic dysfunction to assess benefit from exercise training. <bold>Methods</bold> Cardiopulmonary exercise testing, physical activity steps/day, 6MWD, quality of life (QOL) and symptom questionnaires were performed pre- and post-training (10 weeks, 20 1-hour sessions per week). Immune cell phenotypes were assessed at rest and peak exercise, pre- and post-training. <bold>Results</bold> 14 participants completed training: age 56±11y, 52% females, low normal pulmonary function (FEV1 93%±18), BMI 31.9±8kg/m2. Training compliance was 96%. Post-training exercise tolerance, QOL, fatigue, mental acuity and depression symptoms improved, but not steps/day or 6MWD (<bold>Table 1</bold>). Immune cell numbers (CD3+T, CD19+B, CD4+Th, CD8+T, CD56+NK, FOXP3+Tregs) increased (p<0.05) in response to acute exercise both before and after training. While total monocyte number increased with exercise both pre- and post-training, the percentage of classical inflammatory (CD16++CD14-) (p=0.047) relative to anti-inflammatory, non-classical monocytes (CD16++CD14+) decreased. The exercise-induced response in CD8+ (p=0.013) and FOXP3+TRegs (p<0.026) was augmented post training. <bold>Conclusions</bold> Exercise training was well tolerated in LC patients and improved exercise tolerance, QOL, fatigue, mental acuity, and depression symptoms. We report a possible reduction in inflammatory state with training. <fig><object-id>erj;64/suppl_68/PA5269/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>