- New research found that an increased heart rate can lead to stroke in people with carotid artery stenosis (blocked arteries).
- For people without blocked arteries or minimal blockage, exercise helps maintain healthy blood flow.
- Further research is needed to understand the relationship between elevated heart rate and adverse effects in people with moderate to severe carotid artery stenosis.
- For those with moderate or higher levels of stenosis, lighter forms of exercise such as walking, yoga and balance training are recommended.
While exercise is typically considered good for our health, an elevated heart rate can have negative effects in people with specific health conditions.
According to a new study published in Physics of Fluids an increased heart rate can cause a stroke in people with carotid artery stenosis, a condition that narrows or blocks the arteries.
While the findings are concerning, the prevalence of carotid stenosis remains low, affecting around
Regular exercise supports healthy blood flow among individuals with mild, moderate, or no artery blockage, and is recommended by doctors for heart disease prevention.
For the study, researchers analyzed the impact of heart rates during exercise and resting heart rates.
They used a computational model to stimulate blood flow in the carotid arteries in the following stages of stenosis:
- without blocking
- with a mild 30% blockage
- with a moderate 50% blockage
The findings show that for people with moderate blockage, exercise increases the stress in the blocked area of the arteries, which could cause the stenosis to burst.
Once this blockage reaches the brain, it could lead to an ischemic stroke.
But for individuals without blockage and mild blockage, exercise is beneficial for the stimulated carotid.
Study authorDr. Somnath Roy, PhD, associate professor in the Department of Mechanical Engineering at the Indian Institute of Technology Kharagpur, India, told Healthline that exercise is a common recommendation to prevent cardiovascular disease.
“Existing literature shows that exercise-induced higher pulse rate the stress levels on the artery wall and prevents the formation of stenotic blockage,” Roy said.
“We have observed similar features for healthy arteries through our numerical predictions.”
But for artery models with already progressed stenosis or narrowing, Roy explained there were higher levels of oscillations in WSS (known as oscillatory shear index).
Higher levels of these oscillations may increase the risk of further stenosis progression along with very high shear stress.
If the levels are substantially high, stenotic plaque can start to break up and form blood clots or embolism (a blocked artery caused by a foreign body), which can travel to the brain, block thinner vessels, and result in a stroke.
“The authors have reported the effect of elevated heart rates on hemodynamics[how blood flows] in healthy and stenosed carotid arteries by deploying computational simulations based on physiologically relevant data. it is not a clinical study,” Dr. Joseph C. Maroon, clinical professor, vice chairman, and Heindl scholar in neuroscience at the Department of Neurosurgery at the University of Pittsburgh.
“The observations are of interest. They are suggesting that a 50% or greater stenotic lesion may have increased risk of flow obstruction and thus result in a stroke or heart attack,” Maroon added.
For future studies, the research team plans to investigate the effects of high heart rate at other arterial models like a coronary artery, aorta etc, Roy explained.
Additionally, they plan to look into the effect of changing blood viscosity on the flow features and stress levels. The viscosity of blood may change due to diseases like anemia, leukemia, and sepsis.
They are also looking into the effects of exercise on people with heart valve replacements.
As observed in the study, intense exercise can have adverse effects on patients with moderate or higher levels of stenosis.
“Although flow volume is not reduced until there is 90% or greater stenosis in an artery, the suggestion is that the shear and flow disturbances caused by a 50% narrowing of an artery can disrupt the lining of the artery (the intima) and precipitate clotting and obstruction despite a normal flow,” Maroon said.
“This is an important observation that would need to be further studied and confirmed.”
In understanding more about the relationship between exercise and stenosis, it’s also important to note the potential differences between human heart rate and a computer model.
“Substantial variability in human heart rate (as compared to a computer model) can occur during the course of different-impact workouts, sports, and isometric exercises,” said Dr. Sandra Narayanan, board certified vascular neurologist and neurointerventional surgeon at Pacific Stroke & Neurovascular Center at Pacific Neuroscience Institute in Santa Monica, CA.
“More studies will be needed to understand the relationship between duration of sustained elevated heart rate and adverse impact on cerebrovascular risk in patients with moderate-severe carotid artery stenosis.
Narayanan also explained that it would be helpful to identify if specific activities pose more lifestyle risk, or whether the risk is derived more from tachycardia and is independent of cause.
The study authors suggested a carefully prescribed exercise regimen for people with moderate to severe stenosis or those with a history of stroke.
Roy cautioned that high heart rates resulting from exercise could lead to fatal effects for people with severe stenosis.
He added that arterial blockage might go underreported among athletes or performers until a high heart rate situation arises, the impacts of which could be detrimental.
Regular medical check-ups and opting for lighter exercise patterns would be important for these individuals, Roy said.
“Exercise is good for healthy people to prevent arterial degeneration,” Roy said. “Mild exercise or a moderate increase in heart rate may also be good for people with moderate stenosis.”
Low impact exercises include activities such as walking, yoga and Tai Chi.
“Walk at a normal pace and gradually increasing distance, the elliptical or stationary bike at a comfortable but not short of breath pace, bands for stretching and flexibility,” suggests Maroon.
“Also, balance training can help to avoid falls.”
According to a new study, an increased heart rate can cause a stroke in patients with highly blocked carotid arteries.
Still, the prevalence of carotid stenosis is relatively low in the general population. For patients without blockage or minimal blockage, exercise maintains healthy blood flow.
Regular exercise still offers some of the best protection against heart disease for most people.
Further research is required to understand the connection between exercise-induced heart rate and stenosis.
Experts recommend walking, yoga and balance training for patients with moderate or higher stenosis levels.