Abstract Body (Do not enter title and authors here):
INTRODUCTION: Mechanisms contributing to the post-acute sequelae of SARS-CoV-2 (PASC, aka Long COVID) and associated functional limitations are unclear.

RESEARCH QUESTION: Determine cardiovascular, autonomic and exercise physiology among patients with Long COVID.
METHODS: Twenty-one Long COVID patients (16 females, 41±12yrs) underwent cardiovascular assessment during head-up tilt at supine, 30^o and 60^o, a 10-minute upright standing orthostatic challenge and cardiopulmonary exercise testing (CPET). Baroreceptor sensitivity was determined with Valsalva maneuver. Heart rate (HR) and blood pressure (BP) were monitored continuously. Plasma norepinephrine (NE) was monitored during tilt.

RESULTS: During tilt, HR increased with transition from supine to 30^o and 60^o (72±12 v. 80±14 v. 90±15bpm, P<0.001). Plasma NE increased (2519±896 v. 3407±1085 v. 4025 ±1153pg/mL, P<0.001) and MAP was maintained (92±10 v. 94±10 v. 97±10mmHg, P=0.103). HR increased during Phase IIA of the Valsalva in response to a reduction in systolic blood pressure with group-averaged baroreceptor sensitivity of 8.2±6.0ms/mmHg (Figure 1). During the 10-minute stand, HR increased and BP was maintained (Figure 2). CPET data are presented in Table 1 demonstrating reduced peak oxygen uptake of 19.5±6.7ml/kg/min (74±18% predicted).

CONCLUSIONS: Patients with Long COVID demonstrate preserved autonomic function, with appropriate increase in catecholamines and preservation of blood pressure in response to orthostatic challenge. HR and BP increased appropriately during exercise for the level of work achieved, but overall functional capacity was reduced. Further research is needed to identify novel treatment strategies to improve outcomes.