Objectives: Fatigue is a prominent feature of long COVID (LC) and may be related to several pathophysiologic mechanisms, including immune hyperstimulation. Aerobic endurance exercise training may be a useful therapy, with appropriate attention to preventing post-exertional malaise. Methods: Fourteen participants completed a pilot study of aerobic exercise training (twenty 1.5 h sessions of over 10 weeks). Cardiorespiratory fitness, 6 min walk distance, quality of life, symptoms, 7-day physical activity, immunophenotype, and inflammatory biomarkers were measured before and after exercise training. Results: The participant characteristics at baseline were as follows: 53.5 ± 11.6 yrs, 53% f, BMI 32.5 ± 8.4, 42% ex-smokers, 15.1 ± 8.8 months since initial COVID-19 infection, low normal pulmonary function testing, $\stackrel{.}{\mathrm{V}}$O_2peak 19.3 ± 5.1 mL/kg/min, 87 ± 17% predicted. After exercise training, participants significantly increased their peak work rate (+16 ± 20 W, p = 0.010) and $\stackrel{.}{\mathrm{V}}$O_2peak (+1.55 ± 2.4 mL/kg/min, p = 0.030). Patients reported improvements in fatigue severity (−11%), depression (−42%), anxiety (−29%), and dyspnea level (−46%). There were no changes in 6MW distance or physical activity. The circulating number of CD3+, CD4+, CD19+, CD14++CD16, and CD16++CD14+ monocytes and CD56+ cells (assessed with flow cytometry) increased with acute exercise (rest to peak) and was not diminished or augmented by exercise training. Plasma concentrations of TNF-α, IL-6, IL-8, IL-10, INF-γ, and INF-λ were normal at study entry and not affected by training. Conclusions: Aerobic endurance exercise training in individuals with LC delivered beneficial effects on cardiorespiratory fitness, quality of life, anxiety, depression, and fatigue without detrimental effects on immunologic function.

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by pulmonary and systemic inflammation. Inflammatory mediators show relationships with shortness of breath, exercise intolerance and health related quality of life. Pulmonary rehabilitation (PR), a comprehensive education and exercise training programme, is the most effective therapy for COPD and is associated with reduced exacerbation and hospitalization rates and increased survival. Exercise training, the primary physiological intervention within PR, is known to exert a beneficial anti‐inflammatory effect in health and chronic diseases. The question of this review article is whether exercise training can also make such a beneficial anti‐inflammatory effect in COPD. Experimental studies using smoke exposure mice models suggest that the response of the immune system to exercise training is favourably anti‐inflammatory. However, the evidence about the response of most known inflammatory mediators (C‐reactive protein, tumour necrosis factor α, interleukin 6, interleukin 10) to exercise training in COPD patients is inconsistent, making it difficult to conclude whether regular exercise training has an anti‐inflammatory effect in COPD. It is also unclear whether COPD patients with more persistent inflammation are a subgroup that would benefit more from hypothesized immunomodulatory effects of exercise training (i.e., personalized treatment). Nevertheless, it seems that PR combined with maintenance exercise training (i.e., lifestyle change) might be more beneficial in controlling inflammation and slowing disease progress in COPD patients, specifically in those with early stages of disease.

1. IntroductionAsthma, a heterogeneous disease, is characterized by chronic airway inflammation, leading to variable airflow limitation and resulting in respiratory symptoms like wheezing, shortnes...

The Persistence of SARS-CoV-2 in tissues has been proposed as a driver of prolonged symptoms in long COVID. Pulmonary rehabilitation with exercise training is a well-established intervention for improving symptoms, functional capacity, and inflammation in chronic cardiorespiratory diseases. To investigate whether long COVID is associated with persistent viral or immune-related signals, we analyzed the long RNA profile of circulating extracellular vesicles (EVs) to determine the presence of virus-related transcripts and assess changes in response to exercise training. Fourteen adults with long COVID participated in this single-center pilot clinical trial and completed a 10-week aerobic exercise training program (twenty 1.5 h sessions). Serum-derived EV RNA profiles were analyzed via sequencing at rest (T0) and peak cardiopulmonary exercise testing (T1), before (V2) and after (V24) exercise training. Differentially expressed genes (DEGs) were identified (q < 0.05), and pathway activation analysis was performed. Serum EVs carried diverse RNA species, including protein-coding RNAs, long non-coding RNAs, short non-coding RNAs, and pseudogenes, with no virus-related RNAs detected. No significant DEGs were identified at rest between pre- and post-training, nor in response to acute exercise at pre-training. However, following training, 53 DEGs were found at peak exercise (V24T1) compared to rest (V24T0), including three upregulated genes (ANK3, FTO, FCN1) and 50 downregulated genes (TOP 5: MYL9, NRGN, H2AC6, MAP3K7CL, B2M). These genes were primarily involved in inflammation and metabolism. Pathway analysis revealed significant regulation of 100 pathways at post-training compared to pre training, predominantly inactivated, including pathways involved in inflammation (STAT3 signaling) and metabolism (O-linked glycosylation). Acute exercise and exercise training modulated EV-associated gene expression in long COVID, primarily through transcriptional downregulation. Suppression of inflammation- and immune-related genes post-training highlights potential molecular mechanisms underlying symptom improvement and identifies candidate biomarkers of recovery biology in long COVID. Importantly, while exercise training did not substantially alter EV RNA content at rest, it enhanced the body’s ability to mount a dynamic EV-mediated molecular response during exertion, reflecting improved physiological adaptability. Clinical trial registration number: NCT05398692.