In contrast, the scientists also said in a statement that for healthy patients and those with only slightly blocked arteries, exercise is still beneficial for maintaining healthy blood flow.

Carotid arteries –located on both sides of the neck – supply blood to the brain and facial tissues.

Fat, cholesterol, and other particles building up inside the inner carotid walls can form a plaque that narrows the artery.

That narrowing is called stenosis, which is dangerous because it limits blood flow – and oxygen – to the brain and can cause a stroke. It also can be difficult to detect early in its development.

The elevated heart rate that comes with exercise in a healthy person stabilizes the drag force exerted on the vessel wall, reducing the risk of stenosis. However, the effect can be different for people already experiencing stenosis, the authors of the study said.

“Intense exercise shows adverse effects on patients with moderate or higher stenosis levels,” said Somnath Roy, a study author and an associate professor in mechanical engineering, in the statement. “It substantially increases the shear stress at the stenosis zone, which may cause the stenosis to rupture. This ruptured plaque may then flow to the brain and its blood supply, causing ischemic stroke.”

pll/jha/lpn