Hypertension in African American Women by Carl Castro
NEW HAVEN, Conn.,— With an interest in autonomic control of blood pressure, Peter Latchman, professor of exercise science, said he and his colleagues are working on a discovery that could possibly explain why African-American women are more likely to have hypertension than any other group of people.
“A lot of people say African-American women get high blood pressure because they don’t exercise or they’re not eating properly,” said Latchman. “Those things can cause it, but what exactly are those things doing to the body that is causing the blood pressure to go up? That’s how this all started”
According to the Office on Women’s Health, a subunit of the U.S. Department of Health and Human Services, African-American women develop hypertension earlier in life and have higher average blood pressures compared with Caucasians.
Based on his research, Latchman said there may be a possible connection between the autonomic nervous system in the body and higher tendencies of hypertension—or high blood pressure—in African-American females.
“The autonomic nervous system,” said Latchman, ”is a branch of the nervous system that controls the subconscious activities in the body.”
Latchman said the autonomic nervous system is made up of the sympathetic system— responsible for stimulating the body during fight or flight responses especially, the contracting of blood vessels—and the parasympathetic system, responsible for calming the body back to normal levels.
“When you’re frightened, it’s the sympathetic that makes you breath harder and heart beat faster, and then when you’re calm it’s parasympathetic working,” said Latchman. “So these two systems are constantly fighting for control in the body, but we live because there’s a balance.”
Participants were asked to look at a computer screen that showed a light. Each time the light went up participants were asked to inhale and when the light went down participants exhaled. Participants sat in their chair’s, for seven minutes, breathing heavily while the machines recorded their cardiac activity. During the study, Latchman said there were 42 participants between the ages 18 and 23, consisting of African-American and Caucasian females. In a rested state, participant’s initial weight, height, heart rate and blood pressure is measured and recorded. Then a cuff is fitted on the participant’s finger and is connected to a machine that monitors blood pressure. Electrodes are placed on the body, connected to a machine that monitors the heart rate—an EKG machine.
“All of this (data) is collected and it gives us a number for sympathetic drive and a number for parasympathetic drive” Latchman said. “Anybody with a cardiovascular problem will usually have a high sympathetic drive.”
With the data collected from all participants, Latchman said the African- American females had higher sympathetic drives compared to every Caucasian participant, but those who were considered athletes had normal sympathetic drives.
After the autonomic observation is done, Whitley Roper, graduate major in exercise science, said blood pressure from different arteries throughout the body are checked using a machine called a SphygmoCor. The machine has a probe with sensors at the end of it to—without performing invasive surgery—take cardiac measurements.
Measurements are taken from the carotid artery, in the neck, to the manubrial notch, on top of the chest, and then to the femoral artery, in the leg. The readings are measured twice, when the participant is standing and another while lying down.
“One of the variables we’re looking at is pulse wave velocity,” said Roper. “It tells us about arterial stiffness, how stiff your arteries are. So, if your arteries are stiffer your heart has to work harder to get the blood where it needs to be.”
Latchman said the participants were healthy and didn’t have high blood pressure or any other cardiovascular disease when tested, but the results suggested that the arteries were stiffer in non-athletic African-American women compared to Caucasian participants. A basic conclusion was formulated by the initial data, sympathetic data and the pulse wave velocity data.
“The stiffer the arteries the higher the blood pressure is going to be,” said Latchman. “So a person that already has stiffer arteries to begin with, will get hypertension faster than a person who doesn’t.”
Dr. Matthew Bartels, of Montefiore Medical Center in New York, said he’s been working with Latchman on this study and admits the results are “not set in stone” and said the study still needs to test other variables.
Nicole Darmon, Ph.D in human nutrition, did a study on how social class is related to diet quality. She noticed the more affluent subjects in her study had better diets containing lean meats, fruits and vegetables. The subjects who were closer to poverty had diets rich in refined grain, sugar and fats. “Environment is one of them,” said Bartels. “Socioeconomic lifestyles between the poor and not-so-poor have completely different diets. We need to test participants from these areas to make our study more concrete.”
Darmon’s study also suggests the access to food is a problem for the poor. While supermarkets and grocery stores cluster in affluent neighborhoods, some lower-income neighborhoods have none.
“Having a poor diet can lead to hypertension,” Bartel said. “Your body craves salt, fat, and sugar. While this isn’t harmful to you in moderation, someone who is poor may only be able to afford that kind of food everyday.”
Both Bartel and Latchman agree that the study is still in the early stages. Latchman said he wants to eventually test cardiac output of non-athletic African-American women after following a month long exercise routine.
“This study could lead to creating specialized beta blockers, medication that lowers blood pressure,” said Latchman, “but the most important thing is to spread awareness of cardiac illness to the community that suffers from it the most—African-American women.”