Nitric oxide

https://longcovidatlas.org/glossary/nitric-oxide

In plain language

What it is

A tiny signal the vessel lining releases that tells blood vessels to relax and widen.

Why it matters

Less of it means vessels that do not open up when you need more blood, part of why effort triggers symptoms.

Think of it like

The relax command for your blood vessels. Turn it down and the hoses stay stiff.

For specialists

Formal definition

Endothelium-derived nitric oxide, produced by endothelial nitric oxide synthase, a key vasodilator and inhibitor of platelet aggregation.

Mechanism

Reduced NO bioavailability is a hallmark of endothelial dysfunction and lowers flow-mediated dilation.

Related terms