How blood vessels stay healthy

The inner lining of your blood vessels is a vast, living organ, and a single molecule it makes may be one of the quietest guardians of your health.

Stretched out, the endothelium, the single-cell-thick lining of your blood vessels, would cover a remarkable area. Far from a passive pipe, it is an active organ that constantly senses blood flow and adjusts the vessel around it.

A molecule that keeps vessels open

Much of that work is done by one small molecule: nitric oxide. The endothelium makes it from the amino acid L-arginine, using an enzyme called endothelial nitric oxide synthase.¹ Nitric oxide relaxes the muscle in the vessel wall so blood flows more easily, and at the same time it discourages platelets from sticking and clumping and slows the overgrowth of vascular muscle cells, effects that are, in combination, protective against clots and against the build-up of plaque.¹

The healthy vessel is not a passive pipe. It is a working organ, constantly keeping itself open.

When the lining falters

When the supply or the action of nitric oxide falls, the balance tips toward constriction and inflammation, a state called endothelial dysfunction. It is now recognised as an early step in a range of cardiovascular disorders, including high blood pressure and atherosclerosis.² In many ways, the health of the endothelium is an early readout of cardiovascular health overall.

What helps

Encouragingly, the endothelium responds to how we live. Regular physical activity improves endothelial function and is used in both the prevention and the treatment of cardiovascular disease.³ The quiet lining of the vessels, it turns out, is something we can help look after.