Millions of Americans are at risk of stroke if they exercise too hard, a study suggests.
Researchers found that people with carotid artery stenosis, which affects an estimated five percent of the country, are at risk for sudden clots in the brain from simple activities like a brisk walk, swimming, or even Zumba.
During strenuous exercise, plaque in the great arteries can dislodge and travel to the brain, where it blocks a blood vessel and causes a stroke.
It suggests that as many as 16.5 million Americans may want to refrain from going all out when exercising.
Vigorous exercise may increase your risk of stroke, study suggests (Stock)
Pictured above is a carotid artery with plaques (left) and without plaques (right). Everyone has two carotid arteries that run on either side of the neck (pictured)
Carotid artery stenosis is a condition in which plaques build up in the carotid arteries, narrowing the space through which blood travels.
These arteries run through the neck and are responsible for supplying blood, which contains essential nutrients and oxygen, to the brain and parts of the face.
Sudden increases in blood pressure, such as during exercise, can cause plaques to detach – which can cause a stroke.
The number of Americans with carotid artery stenosis has skyrocketed over the past two decades, figures suggest.
In the early 2000s, it was estimated that about two million Americans had the condition. But now the says about five percent of all adults have the condition ? or 16.5 million people.
Being overweight or obese is a major risk factor for the condition, scientists say. A sedentary lifestyle, diabetes or smoking also increase one’s risk.
In the study, published this week in the journal Physics of Fluidsscientists built a computer simulation of one of the carotid arteries.
They simulated three carotid arteries: one healthy, one with a ‘mild’ blockage of 30 percent and one with a ‘severe’ blockage of 50 percent.
Each was then subjected to an exercise-induced heart rate of 140 beats per minute (bpm), which can be achieved with brisk walking, cycling and Zumba among other activities for the obese.
They were also simulated under conditions of a resting heart rate of 67 and a moderate exercise rate of 100 bpm.
Scientists found that the health of the healthy and slightly blocked carotid arteries improved with exercise.
But for those with severe blockage, the results were described as “worrying.”
The model showed tension in the area increasing the risk of rupturing the stenosis and releasing some of the plaque into the bloodstream.
This can then travel to the brain and become lodged in a blood vessel in the organ, blocking the oxygen supply and causing a stroke.
Dr. Somnath Roy, a mechanical engineer at the Indian Institute of Technology Kharagpur outside Kolkata and lead author of the study, said: ‘Intensive exercise shows adverse effects on patients with moderate or higher levels of stenosis.
‘It significantly increases the shear stress in the stenosis zone, which can cause the stenosis to rupture.
“This ruptured plaque can then flow to the brain and blood supply, causing an ischemic stroke.”
The scientists added in the paper, “While stressful exercise may be beneficial in improving heart function in healthy individuals, the same can be extremely detrimental with increased heart rate due to extensive physical activity for patients with extensive arterial blockages.”
The image above shows carotid arteries below three different beats per minute for the heart and in healthy individuals, as well as those with 30 percent and 50 percent blockage. This was done on the basis of computer models
Previous studies, including one analysis of stroke patients as of 2010, have found that stroke risk at least doubles after exercise.
a meta-analysis of 13,000 strokes in 2021 in Europe also showed that acute anger, emotional distress and strenuous physical exertion were associated with a higher risk of stroke.
The authors noted that all of these increased heart rate, increasing the risk of a plaque detaching and causing a stroke.
Dr. Andrew Smyth, an epidemiologist at the National University of Ireland, Galway, and leader of this study, told TODAY: ‘We believe these trigger events can increase heart rate, increase blood pressure and lead to hormonal changes that affect blood flow in the arteries. change. such as the brain, which can increase the risk of stroke.
That said, not every episode of anger or emotional upset or strenuous physical exertion leads to a stroke.
“Likewise, not every person with a high burden of cardiovascular risk factors will have a stroke.”
Limitations of the latest study included that it was a model and may not accurately represent how events would unfold in real life.
The experts cautioned that the model may have also over-predicted the speed at which blood moved with an increased heart rate, affecting the results.