Millions of Americans are at risk of a stroke if they exercise too hard, a study suggests.
Researchers found people with carotid artery stenosis, estimated to affect five percent of the country, are at risk of suffering sudden clots in the brain from simple activities like a brisk walk, swimming or even Zumba.
During strenuous exercise, plaque in major arteries can become dislodged and travel to the brain where it blocks a blood vessel — causing a stroke.
It suggests that as many as 16.5million Americans may want to refrain from going all-out while they work out.