Study Shows 'Silent' Signs of Hypertension
The higher prevalence of hypertension among African-American women compared with white women is well-documented. Diet and quality of health care have often been identified as likely culprits.
And while they are almost certainly contributing factors to that health disparity, a new Southern study shows evidence of a deeper, physiological factor that appears to be responsible, at least in part, for the difference.
Among young, sedentary women with normal blood pressure readings -- the baroreflex, responsible for the body's ability to stabilize its blood pressure when elevated -- appears to be generally less sensitive in young black women than in their white female peers, according to the study led by Peter Latchman, assistant professor of exercise science. The research shows the baroreflex among the African-American women participating in the test to be 66 percent lower than in the white women tested.
Conversely, sympathetic sensitivity – commonly known as the "fight or flight" response (which raises blood pressure) – is greater among the black women. The study shows that their scores are almost twice as high as white women on this aspect of the testing.
"What we found is that the body's ability to regulate a stable blood pressure was not as strong in young African-American women as it was in young white women," Latchman says. "In effect, these young black women were already showing very early signs of pre-hypertension that were not yet measurable with the standard sphygmomanometer (blood pressure machine)."
The research compares a group of nearly two dozen healthy white women of college age with an almost identical number of healthy black women of the same age. The women are also comparable in health and BMI. While healthy and not having hypertension based on traditional measuring devices, all of the women are living a generally sedentary lifestyle in terms of exercise.
The study was published in the August 2013 edition of the journal, "Clinical Autonomic Research." Latchman was joined in the research by Robert Axtell, graduate coordinator of the Exercise Science Department; Jason Pereira, who was then an SCSU graduate fellow; Gregory Gates of Albert Einstein College of Medicine at Yeshiva University in the Bronx; Matthew Bartels of the Department of Rehabilitation Medicine of Columbia University, and Ronald Edmond DeMeersman of the College of Medicine at Alfaisal University in Riyadh, Saudi Arabia.
Latchman says he hopes the research will enable scientists and the medical community to conduct further studies on this subject and help develop earlier methods of controlling blood pressure in African-American women, before a diagnosis of hypertension or pre-hypertension.
"The mechanisms explaining these differences remain elusive, but future studies examining baroreflex under stressful conditions may provide additional insight into these different responses," he says.
In fact, Latchman already has begun exploring the role of exercise in preventing these very early signs of prehypertension in young black women. That research, while still in process, shows that young, active black women who engage in regular physical activity do not exhibit these same signs, which can set the stage for prehypertension or hypertension. In effect, their results are the same as white women who also participate in regular physical activity.
"That would seem to indicate that exercise among African-American women at a young age could prevent, or at least delay, the start of hypertension," he says. "While this is also true among young, white women, it is even more crucial among young black women because of a predisposition toward high blood pressure."
Latchman adds that this test helps to shed some new light on the seeds of hypertension, especially among African-American women. He said he is unaware of any other research comparing the baroreflex and sympathetic sensitivity of young black and white women who have normal blood pressure readings.