Impact of Presymptomatic COVID-19 on Vascular and Skeletal Muscle Function: A Case Study.

The impact of COVID-19 has been largely described after symptom development. Although the SARS-CoV-2 virus elevates heart rate (HR) prior to symptom onset, whether this virus evokes other presymptomatic alterations is unknown. This Case Study details the presymptomatic impact of COVID-19 on vascular and skeletal muscle function in a young woman (24yrs, 173.5cm, 89kg, BMI: 29.6kg·m-2). Vascular and skeletal muscle function were assessed as part of a separate study with the first and second visits separated by 2 weeks. On the evening following the second visit, the participant developed a fever and a rapid antigen test confirmed a positive COVID-19 diagnosis. Compared to the first visit, the participant presented with a markedly elevated HR (~ 30 bpm) and lower mean blood pressure (~8 mmHg) at the second visit. Vascular function measured by brachial artery flow-mediated dilation, reactive hyperemia, and passive leg movement were all noticeably attenuated (25-65%) as was leg blood flow during knee extension exercise. Muscle strength was diminished as was ADP stimulated respiration (30%), assessed in vitro, while there was a 25% increase in the apparent Km. Lastly, an elevation in IL-10 was observed prior to symptom onset. Notably, 2.5 months after diagnosis symptoms of fatigue and cough were still present. Together, these findings provide unique insight into the physiological responses immediately prior to COVID-19 symptom onset; they suggest that SARS-CoV-2 negatively impacts vascular and skeletal muscle function prior to the onset of common symptoms and may set the stage for the widespread sequelae observed following COVID-19 diagnosis.