Even a slight increase in blood pressure increases the risk of any type of stroke according to new research from the University of Michigan.
Researchers analyzed data from 38,000 participants to study how cumulative blood pressure throughout adulthood influences stroke risk and whether the risk differentiates between races and ethnicities.
“We found that cumulative systolic blood pressure over their life course has a substantial impact on their stroke risk,” said University of Michigan researcher Dr. Deborah Levine.
If a participant's systolic blood pressure exceeds the normal level by more than 10 points, the risk of a stroke caused by bleeding increases by 31%, according to the study, while the risk of a stroke caused by a blocked flow of oxygen rises by 20%.
Blood pressure is a measure of the force that blood exerts on the walls of the arteries. According to the Centers for Disease Control and Prevention, a normal blood pressure reading is less than 120/80 millimeters of mercury (mmHg).
The top number, known as systolic blood pressure, measures the pressure in the arteries when the heart pumps blood during each heartbeat. The bottom number, called diastolic pressure, measures the pressure in the arteries when the heart is at rest between beats.
Even though people who identify as Black and Hispanic have a higher prevalence of stroke and hypertension compared to white adults in the U.S., the study did not show there was a difference in stroke risk between these groups.
“This suggests that controlling blood pressure will reduce stroke risk similarly, in all individuals, regardless of race, ethnicity,” said Levine. “This is especially important for those who are Black or Hispanic.”
The study's findings are not new, but some healthcare officials say the data highlights the correlation between high blood pressure and stroke.
“The study did see what we've seen in prior studies: that African Americans have more ischemic and hemorrhagic strokes than white patients do, and Hispanics tend to have more subliminal hemorrhages, but they couldn't find a correlation with the blood pressure and ethnicity or race,” said Dr. Aniel Majjhoo, chair of the of the Neuroscience Research Council at McLaren Health Care.
Some health care professionals diagnose patients with hypertension or high blood pressure if their blood pressure is consistently reading at 130/80 mmHG or higher.
“Less than 120 mmHG [systolic] is the goal, whereas greater than 140 mmHG, then you definitely have stage two hypertension,” said Majjhoo.
Not exercising enough, eating too much salt, consuming too much alcohol or caffeine and not sleeping enough can lead to elevated blood pressure. Genetics and certain medical conditions like diabetes or kidney disease can also play a role.
“Diet, exercise and sleep are things that can affect your blood pressure,” Majjhoo added. “As well as stress in a patient’s lives can increase blood pressure as well.”
Even though the study demonstrated that blood pressure affects people of all ages, it tends to affect older adults the most.
“About 25% of hypertension is found in patients younger than 40,” said Dr. Anmar Razak, the chief of the Cerebrovascular Disease Division at Michigan State University. “But the grand majority of patients with high blood pressure tend to be 50 or above. 50% are in their 50s and 75% are in their 70s.”
Staying on top of routine checkups can be the first line of defense against high blood pressure.
“I recommend people buy a blood pressure machine and start monitoring the blood pressure themselves at home,” explained Razak.
At-home blood pressure monitors are available at grocery stores and local pharmacies. For accurate readings, healthcare providers recommend purchasing one that’s been tested by the U.S. Blood Pressure Validated Device Listing website.
