A new study from the University of Michigan suggests that if your systolic blood pressure (the top number on your blood pressure reading) is consistently above normal, your risk of stroke increases.
Research published in JAMA Open Network The study found that a systolic blood pressure of 10 points above the 120 mmHg threshold for a sustained period of time increases the risk of ischemic stroke by 20% and the likelihood of intracerebral hemorrhage by 31%.
“We focused on systolic blood pressure because it is the strongest predictor of cardiovascular disease outcomes, particularly stroke but also heart attack,” said Dr. Deborah Levine, professor of medicine at the University of Michigan Medical School and senior author of the study, which analyzed data from more than 38,000 U.S. adults over an average period of 21 years.
“We pooled together six studies that followed participants for many years and enrolled participants of different ages to look at how lifetime high blood pressure affects stroke risk.”
Stroke is 5th leading cause of death According to the Michigan Department of Health and Human Services, high blood pressure is an epidemic in Michigan, causing 5,775 deaths in 2022 alone. More than one-third of Michigan adults have high blood pressure.
“High blood pressure is underdiagnosed, undertreated and undercontrolled,” Levine said, “yet it is the most important risk factor for stroke.”
Levine said the study highlights the importance of detecting high blood pressure early and taking steps to lower it, such as adopting better diet and exercise habits and adding antihypertensive medication when lifestyle changes alone aren’t enough.
“Healthcare providers need to intensify blood pressure treatment to control blood pressure at target levels in all adults,” she said.
Racial differences in stroke incidence
The study looked at data from a diverse patient population: 54% were female, 25% were black, 8.9% were Hispanic, and 66.2% were white.
The researchers found that although black and Hispanic Americans are more susceptible to stroke, there were no racial or ethnic differences in the risk of stroke associated with long-term elevated systolic blood pressure.
“We found no evidence that higher cumulative systolic blood pressure significantly affects stroke risk among black and Hispanic adults compared with white adults,” Levine said, “suggesting that higher blood pressure in these minority groups is likely due to poorer access to health care, treatment and blood pressure management.”
Controlling your blood pressure makes a difference
“Adults should regularly monitor their blood pressure at home to ensure it is at target levels. An annual visit with a healthcare provider is just one part of the time. In addition, my group has shown how home monitoring can improve blood pressure diagnosis and management and that it is an underutilized yet highly effective and cost-effective strategy.”
Because blood pressure readings can be affected by external factors like stress, anxiety, and caffeine and alcohol consumption, Levine recommends that all adults over the age of 30 measure their blood pressure at home twice a day for one week each month. The average of those readings over the week will give you a more accurate picture of what your blood pressure actually is.
Measuring your blood pressure at home also eliminates the “white coat effect,” a phenomenon in which pre-visitor nervousness or anxiety can cause your blood pressure to rise when you’re in the doctor’s office.
Home blood pressure monitors can be purchased for around $20 to $25, and Levin recommends buying a monitor that has been tested on the independent National Blood Pressure Verified Device List website. Click here for detailsand found to provide accurate measurements.
“Unfortunately, most insurance companies don’t cover it,” Levine said. While paying $20 to $25 for a home monitor may not be out of reach for some, others can’t afford the cost, exacerbating health disparities.
“Self-monitoring improves control and is cost-effective, but it remains an underutilized modality and cost is a barrier, making patient education and expanding insurance coverage a priority,” the study authors wrote.
What is high blood pressure?
“Hypertension is defined as a blood pressure reading of 130/80 or higher on two or more occasions,” Levine said.
The top number is your systolic blood pressure, which measures the pressure your artery walls exert every time your heart beats. Your diastolic blood pressure is the bottom number, which measures the pressure your artery walls exert when your heart is resting between beats.
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Until 2017, the threshold for being classified as high blood pressure was set at 140/90 mmHg, but research published around that time led the American Heart Association, American College of Cardiology and other health groups to lower the definition to 130/80 mmHg.
Under the new guidelines, blood pressure levels should be measured two to three times on at least two separate occasions and then averaged.
- The normal range is considered to be below 120/80 mmHg.
- High blood pressure occurs when your systolic blood pressure (the top number) is between 120 and 129 mmHg and your diastolic blood pressure (the bottom number) is less than 80 mmHg.
- Stage 1 hypertension is classified as a systolic blood pressure of 130-139 mmHg or a diastolic blood pressure of 80-89 mmHg.
- Stage 2 hypertension occurs when systolic blood pressure is at least 140 mmHg or diastolic blood pressure is at least 90 mmHg.
- A hypertensive crisis is a medical emergency that occurs when systolic blood pressure exceeds 180 mmHg or diastolic blood pressure exceeds 120 mmHg.
Many people don’t know that the threshold for what constitutes high blood pressure is now lower, Levine said, and some have heard inaccurate information about it.
“When I look at patients who’ve recently had a stroke, it’s disappointing how many of them had high blood pressure before they had a stroke and it wasn’t addressed,” Levine said.
“There’s also a misconception that older people can have high blood pressure and that they don’t need to control it. But that’s not true. All adults should be treated the same, regardless of age.”
Recipes to lower blood pressure
When it comes to high blood pressure, sometimes the best treatment is lifestyle changes, Levine said.
Levine recommends:
- A low-salt diet of less than 1,500 milligrams of salt per day.
- Exercise for 30 minutes, five days a week.
- Weight loss for overweight and obese people Body Mass Index.
- Avoid or limit alcohol intake.
- Ask your doctor if you also need medication to control your blood pressure.
Contact Kristen Shamus at [email protected]. Subscribe to the Free Press.
