There's increasing evidence of a link between racism and high blood pressure. The health condition affects people of all races, but Black Americans are significantly more likely to experience high blood pressure. In fact, they're nearly 50 percent more likely to have hypertension than their white peers, according to the National Center for Health Statistics.
The reasons why are complex and multifaceted, says Quinn Capers, MD, associate dean for faculty diversity and vice chair for diversity and inclusion in the Department of Internal Medicine at UT Southwestern.
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Among them are greater rates of poverty, less healthy diets and environments and higher rates of obesity among Black people, who are 10 percent more likely than white people to have overweight and 30 percent more likely to have obesity, per the U.S. Department of Health and Human Services (HHS). And racism is at the core of many of these factors.
But before we take a closer look at the connection between racism and high blood pressure, let's clarify what blood pressure actually is: a measure of the pressure in your arteries as blood circulates.
Healthy blood pressure is below 120/80 mm Hg (or millimeters of mercury); high blood pressure (or hypertension) is diagnosed when your systolic pressure (the top number, which measures pressure when your heart is beating) is 130 or above or your diastolic pressure (the bottom number, which measures pressure when your heart is between beats) is 80 or above, according to the American Heart Association (AHA).
Left untreated, high blood pressure increases a person's risk for heart attack, stroke and other serious and potentially fatal health conditions, per the AHA.
How Discrimination May Raise the Risk of High Blood Pressure
"Stress from real and perceived discrimination in daily life from structural racism" may be a driving factor behind high blood pressure in Black people, Dr. Capers says, also noting that past research has shown that high levels of stress increase the risk of heart disease. A December 2017 review of studies in Nature Reviews Cardiology found such a link relating to stress in general.
More recently, a July 2020 Hypertension study examined perceptions of varying types of discrimination among Black Americans, concluding that lifetime discrimination may increase their risk of high blood pressure.
The researchers examined data on everyday discrimination, lifetime discrimination and stress from discrimination among 1,845 Black adults from Mississippi between 2000 and 2013 who did not have high blood pressure in the initial years of the study.
They found that participants who reported high or medium levels of lifetime discrimination had a 34 percent and 49 percent increased risk for hypertension respectively, compared to those who reported low levels, after accounting for other risk factors such as age, sex, socioeconomic status, body mass index, diet and physical activity.
Everyday discrimination was not associated with an increased risk of high blood pressure after adjusting for other risk factors. "The everyday discrimination scale captures minor day-to-day occurrences of discrimination, which may be more likely to affect short-term changes in blood pressure," the study authors wrote.
In other words, a single incident of discrimination may raise your blood pressure for a moment, but not necessarily keep it elevated. The authors suggest that at-home blood pressure monitoring may be required to pick up such fluctuations.
In contrast, lifetime discrimination may better reflect the effects of cumulative exposure to bias over the years, and therefore may be more likely to be detected in higher blood pressure measurements over multiple doctor visits.
The findings demonstrate the effect of cumulative exposure to stressors over a lifetime and the physiological reactions to stress that contribute to poor health, the study's lead author Allana T. Forde, PhD, MPH, said in a statement.
"Health care professionals who understand the importance of unique stressors like discrimination that impact the health of African Americans will be better equipped to provide optimal patient care to this population," Forde said.
Dr. Capers says that the findings are important when viewed through the lens of stress. "Being a subject to racism is a psychological stress. Stress causes the release of hormones like cortisol, adrenaline and others that result in arteries clamping down and the heart speeding up. These processes cause a transient elevation of blood pressure." But after "exposure to this psychological stressor for most hours of the day, chronic hypertension could develop," he says.
However, he adds, "I don't know if we have enough information to say that they are independent risk factors, but they may be. I feel more confident stating that racism in association with other risk factors can exacerbate the risk of hypertension."
"The idea is that constant stress creates this wearing down that happens at a physiological level and it leads to chronic disease."
Indeed, it's nearly impossible to untangle the influence of diet, obesity, activity, environment and socioeconomic status from discrimination in the study's results, as much as the authors tried to, says New Orleans-based cardiologist and Tulane University professor Keith C. Ferdinand, MD.
"Racism is more structural, and I think in a way explains the more complex interaction between the environment [and the person], whereas [perceived] discrimination is what a person feels about the environment," he says. (Neither Dr. Ferdinand nor Dr. Capers was involved in the Hypertension study.)
The Chronic Effects of Weathering
That more subtle effect is captured in a popular concept in the study of racial health disparities known as weathering.
"Weathering means like a constant exposure and a wearing down," explains S. Michelle Ogunwole, MD, a health disparities researcher and social epidemiologist at Johns Hopkins Medicine in Baltimore, Maryland. "The idea is that constant stress creates this wearing down that happens at a physiological level and it leads to chronic disease."
First identified by public health researcher Arline T. Geronimus in a 1992 article in Ethnicity and Disease, weathering proposes that the health of Black people in America is subject to early deterioration as a consequence of social exclusion and the chronic stress it causes, independent of the effects of poverty, as demonstrated in more recent research, including a May 2006 report in the American Journal of Public Health and a June 2020 study in the Journal of Ethnic and Racial Health Disparities.
The regular release of stress hormones such as cortisol or immune responses that lead to inflammation can lead to chronic disease, worsen it or even raise the risk of obesity, Dr. Ogunwole says.
Chronic stress resulting from perceived racism can also affect the way your heart rate reacts, says Anuj Shah, MD, an interventional cardiologist in Irvington, New Jersey. "It impacts something called heart rate variability, which relates to your heart's ability to go in and out of the flight-or-fight response."
Heart rate variability is a biomarker that measures the time between heartbeats. If your system is in fight-or-flight mode, the variation in time between heartbeats will be low, Dr. Shah explains. Very poor heart rate variability can be a sign of chronic stress, he says, and people with low heart rate variability are more likely to have high blood pressure and worse cardiovascular health in general, he adds.
Lifetime discrimination, threats associated with discrimination and being physically harassed in a discriminatory manner were associated with lower heart rate variability in a January 2018 Cultural Diversity and Ethnic Minority Psychology study involving 103 college students who identified as African American.
Socioeconomic disadvantage plays a key role in the quality of health care that Black people receive, Dr. Shah says. The Black poverty rate is more than twice that of white people, according to the Kaiser Family Foundation.
"Income inequality is linked to insurance inequality, which leads to medication inequality," and not being able to access the best medical care, Dr. Shah says — for high blood pressure and any number of other health concerns.
But the problem goes deeper than what an individual can afford; there's a complex array of socioeconomic factors that affect a person's wellbeing — including the effects of racism — known as social determinants of health. Dr. Ferdinand describes them as being related to "the environment where a person is born, works, lives and plays."
The HHS elaborates: "Entrenched, institutionalized patterns — such as the racial segregation of residential areas — can be so deeply embedded that they persist without anyone intending to discriminate."
These patterns result in factors like unstable housing, poverty, unsafe neighborhoods or substandard education, which are linked with higher rates of high blood pressure, according to the Centers for Disease Control and Prevention (CDC).
The Influence of Diet
A diet high in salt, fried food, fat, bread and sweetened beverages is an important risk factor for hypertension in some Black people, Dr. Ferdinand says.
He points to prior research that found a typical Southern dietary pattern accounted for 52 percent of the excess risk of high blood pressure among Black men and 29 percent of the excess risk among Black women, compared with their white counterparts. That research, published October 2018 in JAMA, analyzed data from nearly 7,000 adults over nine years.
"Decreasing sodium intake to less than 2,300 milligrams a day is extremely important to help control blood pressure," Dr. Ferdinand says, yet the AHA reports that the average American adult takes in more than 3,400 milligrams per day.
Black adults are also more likely to be salt-sensitive, meaning the effects of a high-salt diet are more dramatic on their risk of high blood pressure, according to the AHA. Salt-sensitivity has been linked to low levels of the enzyme renin, and Black people are more likely than their white counterparts to have low renin, according to a February 2013 review in the Journal of the American Society of Hypertension.
Some research has observed differences between Black and white adults in a biochemical pathway called the renin-angiotensin-aldosterone (RAA) system, Dr. Shah says, such as a June 2018 Hypertension report and a September 2014 article in the World Journal of Cardiology.
Certain blood pressure medications block a hormone relating to the RAA system. When these medications are used alone, Black patients are, on average, less responsive than white patients, which may be because of the link to lower renin levels, according to a May 2018 review of studies in the Annals of Pharmacotherapy.
However, though he still recommends limiting sodium intake, Dr. Ferdinand says there isn't universal agreement on such findings. More research is needed on the effects of diet and the enzyme renin when it comes to Black Americans' risk of hypertension.
High Blood Pressure and COVID-19
Black people are four times more likely to be hospitalized from COVID-19 than white people, according to the CDC.
Further, a May 2020 JAMA study of 5,700 COVID-19 hospitalizations in New York City found that the most common underlying condition — a risk factor for more serious disease — in patients was hypertension.
“COVID-19 and cardiovascular disease are very closely tied with each other, and African Americans definitely end up doing poorer,” Dr. Shah says.
It's possible this is at least in part due to differences in that same RAA system, but more research is needed, according to a July 2020 op-ed by Greek researchers in the Journal of Human Hypertension.
How to Close the Racial Blood Pressure Gap
It shouldn't fall to Black people to fix the systemic racism that contributes to unequal health. There are steps that all individuals, policymakers and health care systems can take to help address the issue.
Acknowledge Racism Is a Public Health Problem
Health care systems and policymakers must take socioeconomic and environmental inequities into account, Dr. Capers says. "Treat racism as the public health problem that it is, and work to dismantle racism in policing, school systems, banking systems, etc."
Training more clinicians and researchers of color can help, Dr. Capers says, as can recruiting more Black people to participate in clinical research trials of blood pressure treatments. This is a crucial step in better understanding the way the disease works in different populations. Volunteers can join clinical research trials by visiting the U.S. National Library of Medicine's database at ClinicalTrials.gov.
People of all races should continue speaking out against racism and raising awareness of the public health concerns of injustice. Consider donating time and/or money to local organizations that are actively working to combat health inequities, such as:
Black patients can advocate for optimal health care by:
- Seeking out care providers you feel comfortable with
- Preparing questions beforehand and asking plenty during an appointment
- Speaking up if you feel you're receiving subpar care
Involve Community Members in Education and Outreach
Primary care systems, in particular, aren't really set up to address health disparities in chronic diseases, such as high blood pressure, Dr. Ogunwole says. This is true even if doctors have a genuine desire to be more effective in treating their patients of color.
"That's why we also rely on community health workers, people who are from the communities that our patients are from, who may speak their language, who can encourage them and spend more time with them than sometimes even physicians do," she says.
Barbershops have been particularly effective in this way. For example, an April 2018 study in The New England Journal of Medicine examined the effects of an intervention in which barbers educated Black male clients with high blood pressure, and then encouraged them to meet with pharmacists in the barbershops. Compared to a group of men who were instead encouraged to implement lifestyle changes and visit their doctors, the men who met with pharmacists at their barbershops saw greater reductions in their blood pressure over the six-month study period.
The researchers speculated that the trusted relationship between Black barbers and their clients, combined with peer support among barbershop patrons, may have factored into the success of the intervention. Black men interact with health care providers less often than Black women, the researchers noted, so engaging them outside of the clinical setting ensures more are being treated for high blood pressure.
Community leaders can develop relationships with trusted local health care providers who can help bring blood pressure education and resources to less medicalized settings. And individuals can make a difference, too: Talking to friends and family about the dangers of high blood pressure — and the fact that it can be managed — may encourage them to take it seriously and ultimately get help for the condition.
Make Lifestyle Choices to Lower Your Risk
Dr. Capers' advice to Black people who want to lower their own risk for hypertension or manage high blood pressure is to control what you can.
"Eat healthy — more fruits and vegetables, less fried foods and high-calorie, high-salt foods. Try to maintain a healthy body weight; exercise 30 minutes a day in at least a brisk walk; learn relaxation techniques; nurture loving relationships with your family and friends; lean on your faith. All of these things can help reduce elevated blood pressure or stress."
- ACC and AHA: "2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults"
- National Center for Health Statistics: "Hypertension Prevalence and Control Among Adults: United States, 2011–2014"
- HHS: "Obesity and African Americans"
- Hypertension: "Discrimination and Hypertension Risk Among African Americans in the Jackson Heart Study"
- Cultural Diversity and Ethnic Minority Psychology: "Examining the Association Between Perceived Discrimination and Heart Rate Variability in African Americans"
- Journal of the American Society of Hypertension: "Salt Sensitivity: A Review with a Focus on Non-Hispanic Blacks and Hispanics"
- JAMA: "Association of Clinical and Social Factors With Excess Hypertension Risk in Black Compared With White US Adults"
- AHA: "How Much Sodium Should I Eat Per Day?"
- Nature: "COVID19 and Increased Mortality in African Americans: Socioeconomic Differences or Does the Renin Angiotensin System Also Contribute?"
- CDC: "COVID-19 Hospitalization and Death by Race/Ethnicity"
- JAMA: "Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area"
- Nature Reviews Cardiology: "Effects of Stress on the Development and Progression of Cardiovascular Disease"
- AHA: "Lifetime Discrimination May Increase Risk of Hypertension among African Americans"
- Ethnicity and Disease: "The weathering hypothesis and the health of African-American women and infants: evidence and speculations"
- AHA: "High Blood Pressure and African Americans"
- Kaiser Family Foundation: "Poverty Rate by Race/Ethnicity"
- Annals of Pharmacotherapy: "A Review of ACE Inhibitors and ARBs in Black Patients With Hypertension"
- Journal of Ethnic and Racial Health Disparities: "Racial Discrimination, Inflammation, and Chronic Illness Among African American Women at Midlife: Support for the Weathering Perspective"
- American Journal of Public Health: "'Weathering' and Age Patterns of Allostatic Load Scores Among Blacks and Whites in the United States"
- NEJM: "A Cluster-Randomized Trial of Blood-Pressure Reduction in Black Barbershops"
- HHS: "Healthy People 2020: An Opportunity to Address Societal Determinants of Health in the United States"
- CDC: "Fact Sheet: Health Disparities in Hypertension and Hypertension Control"
- Hypertension: "Individualized Therapy Based on Renin/Aldosterone Phenotyping"
- World Journal of Caridology: "African Americans, hypertension and the renin angiotensin system"
- AHA: "Health Threats From High Blood Pressure"
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