Individuals With Post-Acute Sequelae Of COVID-19 Have Impaired Endothelial Function, But Combined Exercise Training Restores Endothelial Function

PURPOSE: COVID-19 infection is associated with persistent impaired endothelial function, but it remains unclear whether individuals with post-acute sequelae of COVID-19 (PASC) exhibit impaired endothelial function. Furthermore, the role of exercise training in restoring endothelial function in this population is not well understood. The aim of this study was to investigate whether individuals with PASC exhibit lower endothelial function compared to healthy individuals, and whether combined exercise training can restore endothelial function in individuals with PASC. METHODS: We employed two approaches. Study I involved a cross-sectional study comparing endothelial function between individuals with PASC (n = 20, aged 22.8 ± 3.2 years) and healthy individuals (n = 42, aged 21.7 ± 2.0 years). Study II, an intervention study, aimed to determine if combined exercise training could partially reverse the decline in endothelial function associated with PASC. Twenty individuals with PASC were randomly assigned to either the combined exercise group (EX; n = 10), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control group (CON; n = 10). Endothelial function was measured by flow-mediated dilation (FMD) of the brachial artery. Cardiorespiratory fitness, indicated by VO2peak, and patient-reported symptoms of dyspnea and fatigue were also evaluated at baseline and after the 8-week intervention. RESULTS: Firstly, individuals with PACS exhibited significantly lower FMD compared to healthy individuals (4.74 ± 1.7% vs 8.00 ± 2.3%, p < 0.001). Secondly, EX group showed a significant increase in FMD (EX: 4.63 ± 1.7% to 8.32 ± 2.5%, CON: 5.05 ± 1.5% to 6.07 ± 1.8%, interaction: p = 0.015), reaching levels similar to those of the healthy individuals. The EX group demonstrated a significant increase in VO2peak (p < 0.001) and improvements in dyspnea and fatigue symptoms compared to the CON group (p < 0.05). CONCLUSION: These findings indicate that individuals with PASC have lower endothelial function compared to healthy individuals, but combined exercise training can effectively restore endothelial function in individuals with PASC. Therefore, exercise training may serve as an effective lifestyle intervention to improve vascular function in individuals with PASC. This work was supported by the Basic Study and Interdisciplinary R&D Foundation Fund of the University of Seoul (2022)