Endothelial Function Does Not Show Signs of Impairment in Young Athletes At Two Months Post‐Covid‐19 Infection

Abstract

It has been almost two years since the Covid‐19 pandemic hit, with over 5 million deaths globally. It is known that endothelial activation and dysfunction play a crucial role in Covid‐19 pathogenesis. Evidence of widespread endothelial injury is found in advanced cases of Covid‐19, especially in people with cardiovascular comorbidities. However, the effects of Covid‐19 on endothelial function in unique cohorts such as young athletes have been largely unexplored. This study evaluated endothelium function by noninvasive flow‐mediated dilation (FMD) in a sample of 14 college athletes (10M/4F, 18‐23 yrs, BMI, 23.8 ± 1.6 kg/m2) after testing positive for Covid‐19. All athletes had Covid‐19 with mild or no symptoms and did not require hospitalization. The study was performed 24 ± 10 days (13‐44 days) after having Covid‐19 positive tests. We also involved 10 BMI similar healthy young subjects as controls (7M/3F, 20‐25 yrs, BMI, 24.2±2.0 kg/m2). Baseline brachial artery diameters and the largest diameters after post cuff release were measured to calculate FMD. Brachial blood flow mean velocities and diameters were also recorded within 20 seconds after cuff release for calculating the shear rate (8 * mean velocity/ diameter). The baseline brachial artery diameter was significantly larger in the athlete group versus the control group (4.32±0.63 mm vs. 3.54±0.42 mm, p=0.02). The FMD was significantly lower in the athlete group than in the control group (6.49±2.05% vs. 11.05±4.08%, p=0.02). This finding is consistent with the previous reports that FMD was significantly lower in healthy athletes compared with controls. However, FMD adjusted for the ratio of flow‐mediated dilation and shear rate did not show a statistical difference between groups (0.058±0.028 %/s‐1 vs. 0.076±0.056 %/s‐1, p=0.33), even after evaluating baseline diameter as a covariate. Despite the need for extended acute and chronic observations and a healthy athlete control group, our findings suggest endothelial resilience in response to Covid‐19 infection in young athletes, which may explain their mild or asymptomatic status.