(RxWiki News) The increased risk of heart problems in patients with elevated blood pressure is well-established. But lower blood pressure may not decrease the risk of stroke, heart attack and other complications.
New research reinforced the connection between high blood pressure and higher risk for heart problems.
But the researchers did not observe any link between lower-than-normal blood pressure and a decreased risk of heart-related conditions.
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The study was conducted by Carlos Rodriguez, MD, MPH, of the Department of Medicine and Public Health Sciences at the Wake Forest University School of Medicine in Winston-Salem, NC, and colleagues.
Existing research indicates an increasing risk of heart disease as systolic blood pressure rises above 115 millimeters of mercury (mmHG).
Systolic blood pressure is the measurement of the force applied to artery walls as the heart pumps blood through the body. A normal reading for blood pressure is below 120 mmHG. High blood pressure is also called hypertension.
The researchers set out to study whether a systolic blood pressure lower than 120 mmHG corresponded to a lower risk of heart failure, heart attack or stroke.
The team studied 4,480 patients with high blood pressure but without heart disease. They took blood pressure readings to set a baseline. The study authors then took blood pressure readings three times each year for three years, ending in 1989.
For the study, the authors considered a systolic blood pressure of 140 mmHG to be “elevated.” Readings between 120 mmHG and 139 mmHG were “standard,” and less than 120 mmHG was “low.”
The researchers also collected data about participants' age, sex, diabetes status, cholesterol levels, smoking status and alcohol consumption.
The patients had a total of 1,622 cardiovascular events, including heart attacks and strokes, during the study period.
Participants with high blood pressure were 1.46 times more likely than those with low blood pressure to have a heart-related event.
The researchers found no difference in heart problems between the standard and low groups, which was contrary to their expectations. They found that, once blood pressure reached normal levels, lower blood pressure provided no additional benefits.
The authors noted that their work still reinforced the importance of controlling high blood pressure.
The study was published online June 16 by the peer-reviewed journal JAMA Internal Medicine.
The National Heart, Lung and Blood Institute provided funding. The authors did not disclose any conflicts of interest.