Named the danger of excessive physical exertion for millions of people

A new study shows that millions of people are at risk of stroke if they exercise too hard.

Researchers have found that people with carotid stenosis, which is estimated to affect five percent of the US population, are at risk of sudden blood clots in the brain from simple activities such as brisk walking, swimming or even Zumba.

During intense exercise, plaques in large arteries can shift and travel to the brain, where they block a blood vessel, causing a stroke.

This suggests that as many as 16.5 million Americans may want to refrain from going all out while exercising, the Daily Mail notes.

As the publication explains, carotid stenosis is a condition in which plaque accumulates in the carotid arteries, narrowing the space through which blood flows. These arteries run through the neck and are responsible for delivering blood containing vital nutrients and oxygen to the brain and parts of the face. A sudden increase in blood pressure, such as during exercise, can cause plaque to shift, which can lead to a stroke.

The numbers suggest that the number of Americans with carotid stenosis has skyrocketed over the past two decades. In the early 2000s, an estimated two million Americans suffered from the disease. But the Cleveland Clinic now claims that about five percent of all adults, or 16.5 million people, suffer from the disease.

Scientists say being overweight or obese is a major risk factor for developing this disease. A sedentary lifestyle, diabetes, or smoking also increase someone’s risk.

In a study published this week in the journal Physics of Fluids, scientists built a computer simulation of one of the carotid arteries. They simulated three carotid arteries: healthy, one with a “mild” 30 percent blockage, and one with a “severe” 50 percent blockage. They were then each subjected to an exercise-induced heart rate of 140 beats per minute, which can be achieved with brisk walking, cycling, and Zumba, among other activities for people with obesity.

Scientists have found that exercise improves the health of healthy and slightly clogged carotid arteries. But for those who had a severe blockage, the results were described as “worrisome”.

The model showed a load on the area, which increased the risk of rupture of the stenosis and the entry of part of the plaque into the bloodstream. It can then travel to the brain and get stuck in a blood vessel inside the organ, blocking the oxygen supply and causing a stroke.

Dr. Somnath Roy, a mechanical engineer at the Indian Institute of Technology Kharagpur outside Calcutta and lead author of the study, said: “Intense exercise has an adverse effect on patients with moderate or higher levels of stenosis. This significantly increases the shear stress in the stenosis, which can This ruptured plaque can then travel to the brain and its blood supply, causing an ischemic stroke.”

The scientists added in the article: “While stressful exercise may be beneficial in improving cardiac performance in healthy individuals, the same can lead to extremely adverse effects in increased heart rate due to intense exercise in patients with extensive arterial blockages.”

Previous studies, including an analysis of stroke patients in 2010, have shown that the risk of stroke is at least doubled after exercise.

A meta-analysis of 13,000 strokes in 2021 in Europe also found that acute anger, emotional distress and strenuous exercise were associated with a higher risk of stroke.

The authors noted that all this increases the heart rate, increasing the risk of plaque displacement and causing a stroke.

Dr. Andrew Smith, an epidemiologist at the National University of Ireland Galway and leader of this study, said: “We believe that these trigger events can increase heart rate, increase blood pressure and lead to hormonal changes that alter blood flow in the vascular beds, such as brain, which can increase the risk of stroke. However, not every bout of anger, emotional upset, or heavy physical exertion leads to a stroke. Similarly, not every person with high levels of cardiovascular risk factors will have a stroke.”

The limitations of the latest study were that it was a model and may not accurately reflect how events would play out in real life.

The experts warned that the model may also have overestimated the speed of blood movement at elevated heart rates, which affected the results.