While working out benefits most people, new research suggests that intense workouts could cause a stroke in those with moderate carotid artery blockage.
Atherosclerosis is the buildup of plaque on the inner lining of arteries, which causes them to narrow. It can occur in any artery, including the neck's carotid arteries.
If the buildup creates a partial or complete blockage, blood flow to the area of the body fed by the artery is reduced or cut off — resulting in a heart attack, stroke, or tissue death. In addition, plaque fragments can break free from the blocked area and travel throughout the bloodstream, resulting in a blood clot in the body or an ischemic stroke in the brain.
However, people with atherosclerosis in a carotid artery might not know they have the condition, as it may not cause symptoms until the blockage is severe.
And while exercise is generally beneficial for most people, researchers from the Indian Institute of Technology Kharagpur, West Bengal, India, wondered whether the increased heart rate that occurs during exercise could cause a stroke in those with mild to moderate carotid artery blockages. If so, it could help healthcare providers prescribe better exercise regimens for people with this condition.
Their study, published on June 20 in Physics of Fluids, revealed some concerning findings suggesting that people who engage in intense workouts should consider checking their carotid artery health regularly.
Using a specialized computational model, the researchers simulated carotid artery blood flow in three stages of artery narrowing. These included no blockage, mild 30% blockage, and moderate 50% blockage. The team then compared the effects of heart rates at 140, 100, and 67 beats per minute on the artery models.
The scientists found that exercise improved the condition of the non-blocked carotid artery model. However, in the moderately blocked artery, elevated heart rates during a workout increased the chance of plaque breaking free — which theoretically could result in ischemic stroke. In addition, the elevated heart rate could cause more artery narrowing.
The study authors say an elevated heart rate substantially increases the sheer stress at the narrowed area in the artery, which may cause the area to rupture — sending plaque fragments to the vessels in the brain.
While the study involved computational models and not animals or humans, the scientists say that because some people might not realize they have atherosclerosis, individuals who engage in intense exercise should consider having regular carotid artery checkups.
In addition, they recommend that people with moderate to severe carotid artery blockages or a history of stroke should adhere to a carefully designed exercise plan to reduce the chances of experiencing an initial or subsequent stroke.
- American Heart Association. What is Atherosclerosis?
- Physics of Fluids. Effect of heart rate on the hemodynamics in healthy and stenosed carotid arteries.