Hyperaemia during dynamic handgrip exercise is preserved in healthy young subjects after recovery from COVID-19

We sought to investigate possible impaired hyperaemia during dynamic handgrip exercise (HGE) in young healthy individuals who had recovered from COVID-19. We tested the vascular function in individuals recovered from COVID-19 using a nitric oxide donor (i.e., sodium nitroprusside; SNP), which could revert a possible impaired endothelial function during HGE. Further, we tested whether individuals who recovered from COVID-19 would present exaggerated brachial vascular resistance under an adrenergic agonist (i.e., phenylephrine; PHE) stimuli during HGE. Participants were distributed into two groups: healthy controls (Control; men: n = 6, 30 +/- 3 years, 26 +/- 1 kg/m2; and women: n = 5, 25 +/- 1 years, 25 +/- 1 kg/m2) and subjects recovered from COVID-19 (post-COVID; men: n = 6, 29 +/- 3 years, 25 +/- 1 kg/m2; and women: n = 10, 32 +/- 4 years, 22 +/- 1 kg/m2). Participants in the post-COVID group tested positive (RT-PCR) 12-14 weeks before the protocol. Heart rate (HR), brachial blood pressure (BP), brachial blood flow (BBF) and vascular conductance (BVC) at rest were not different between groups. The HGE increased HR (Control: Delta 9 +/- 0.4 bpm; and post-COVID: Delta 11 +/- 0.4 bpm) and BP (Control: Delta 6 +/- 1 mmHg; and post-COVID: Delta 12 +/- 0.6 mmHg) in both groups. Likewise, BBF (Control: Delta 632 +/- 38 ml/min; and post-COVID: Delta 620 +/- 27 ml/min) and BVC (Control: Delta 6.6 +/- 0.4 ml/min/mmHg; and post-COVID: Delta 6.1 +/- 0.3 ml/min/mmHg) increased during HGE. SNP did not change HGE-induced hyperaemia but did decrease BP, which induced a reflex-related increase in HR. PHE infusion also did not change the HGE-induced hyperaemia but raised BP and reduced HR. In conclusion, exercise-induced hyperaemia is preserved in healthy young subjects 12-14 weeks after recovery from COVID-19 infection. What is the central question of this study? How does vascular function compare during dynamic handgrip exercise in young healthy adult males and females who recovered from COVID-19? What is the main finding and its importance? No differences were observed in exercise hyperaemia in healthy young adults, males and females, who recovered from COVID-19 compared to the healthy control group. Vascular function seems to be preserved in individuals 12-14 weeks after COVID-19 during dynamic handgrip exercise in young healthy adults, males and females.