DURHAM, N.C. -- Researchers at Duke University Medical Center have shown
that face-to-face encounters with racism can overwork the heart and elevate
blood pressure in African Americans, symptoms that are known to boost the
risk of heart disease and other illnesses.
The researchers said their findings suggest that exposure to the chronic
stress of racism is one factor that may contribute to higher rates and more
severe cases of heart disease and hypertension among African Americans.
Results of the study were published in the July issue of the International
Journal of Behavioral Medicine
In the study of 30 healthy African-American women, the researchers found
that direct racist provocation from a white opponent caused a significant,
immediate and prolonged increase in heart rate and blood pressure as well
as strong feelings of anger, resentment, cynicism and anxiety -- emotions
that have been shown to prompt the release of damaging stress hormones such
as adrenalin and cortisol, the Duke scientists said.
"It is well-documented that racism has negative social, economic and
political consequences on African Americans, but the direct effects of racism
on physical and emotional health have only begun to be explored," said
Maya McNeilly, an assistant medical research professor of psychiatry at
Duke. "Documenting and quantifying racism's deleterious effects will
help provide the clout needed to lobby for societal change."
In addition, determining how people cope with racism and identifying factors
that buffer its effects will help in developing interventions to reduce
the negative effects of racism, she said.
McNeilly's research is supported by a $1 million grant from the National
Institute on Aging that funds the Duke Exploratory Center for Research on
Health Promotion in Older Minority Populations. One of seven such centers
in the nation, its purpose is to study the ways in which psychosocial factors
such as stress, religion, social support, personality and racism influence
the risk of developing chronic diseases -- including cardiovascular disease,
hypertenstion, diabetes and cancer -- in older African Americans.
In the current study, subjects were asked to participate in two debates
against a white experimenter -- one debate on a racial topic and one debate
on a controversial but non-racial topic. Researchers measured how subjects
reacted when actively engaged in responding to provocation and while passively
engaged in listening to inflammatory comments. During each debate, the subject
was joined by an African-American "confederate" who either provided
supportive comments and gestures (eye contact, nodding or saying "yes"
or "right") to the subject or sat quietly throughout the debate
without making eye contact.
The subjects had the strongest emotional and physical reactions during
the racial debate, regardless of whether they were speaking or listening,
and those reactions persisted throughout the 10-minute recovery period following
the debate. Subjects reported less anger when they received social support
from the African-American confederate, but social support had no immediate
effect on lowering blood pressure or heart rate during the experiment.
McNeilly says the long-term effects of social support need to be researched
further because previous studies have shown that social support does, indeed,
have beneficial effects on health, including reduced rates of morbidity
and mortality. However, she said these benefits are influenced by a number
of other factors, such as gender, culture, age, and the nature of the relationship,
so the direct impact of social support is difficult to gauge.
McNeilly's study builds on a wide body of research at Duke, led by Dr.
Redford Williams, Normal Anderson and James Blumenthal, that examines the
impact of mental stress on physical health. Decades of their research have
shown that mental stress caused by factors such as parenting, working, marriage,
watching violent movies and having a hostile personality can increase the
risk of heart disease by raising blood pressure, heart rate and stress hormone
production. An excess of stress hormones can damage the cardiovascular system
over time by increasing blood pressure, heart rate, and blood flow to the
muscles, according to the Duke researchers.
"There is a growing body of evidence suggesting that social support
exerts a buffering effect by ameliorating the damaging effects of stress
on physical and mental health," McNeilly said. "And many epidemiologic
studies suggest that social support is related to reduced morbidity and
mortality, particularly for cardiovascular disease."
McNeilly plans to broaden her research on the health effects of racism
by studying gender discrimination, discrimination within the same race,
and racism's effects on other ethnic groups. Included in that research will
be studies examining the physiologic mechanisms by which racism affects
physical health as well as factors that can buffer its detrimental effects.