The impact of COVID-19 on cardiorespiratory fitness (CRF) is negative, increasing the likelihood of exertional symptoms such as fatigue and shortness of breath, and adversely affecting vascular function, impairing cardiovascular health. This study investigated endothelial function and its relationship with CRF in patients who have recovered COVID-19. Patients were evaluated 1 month after infection, including clinical assessment, pulmonary function, endothelial function (measured by flow-mediated dilation), and cardiopulmonary exercise testing. COVID-19 survivors exhibited reduced exercise capacity, with poor values of peak V̇O