Carotid body dysregulation contributes to the enigma of long COVID

The symptoms of long COVID, which include fatigue, breathlessness, dysregulated breathing, and exercise intolerance, have unknown mechanisms. These symptoms are also observed in heart failure and are partially driven by increased sensitivity of the carotid chemoreflex. As the carotid body has an abundance of ACE2 (the cell entry mechanism for SARS-CoV-2), we investigated whether carotid chemoreflex sensitivity was elevated in participants with long COVID. During cardiopulmonary exercise testing, the V E /VCO 2 slope (a measure of breathing efficiency) was higher in the long COVID group than in the controls, indicating excessive hyperventilation. The hypoxic ventilatory response, which measures carotid chemoreflex sensitivity, was increased in long COVID participants and correlated with the V E /VCO 2 slope, suggesting that excessive hyperventilation may be related to carotid body hypersensitivity. Therefore, the carotid chemoreflex is sensitized in long COVID and may explain dysregulated breathing and exercise intolerance in these participants. Tempering carotid body excitability may be a viable treatment option for long COVID patients.