Fackelmann, Kathleen, Science News
The patient takes one look at the cardiologist and his blood pressure shoots through the roof. As soon as the doctor leaves the room, the pressure eases.
The patient calls it stress. Physicians, however, refer to this condition as white-coat hypertension. People with white-coat hypertension experience a sudden surge in blood pressure during a medical exam.
There's no controversy about the dangers associated with the better known chronic high blood pressure. People with such hypertension face an increased risk of stroke, heart attack, kidney disease, and heart failure--in which the heart progressively weakens and ultimately stops. But do transient surges in blood pressure do any harm?
Some researchers contend they do not. Others believe that white-coat hypertension represents a fairly serious cardiovascular risk factor. A German team now weighs in with findings suggesting that potentially dangerous thickening of the heart walls appears unusually often in people with white-coat hypertension.
"It seems this group is not as healthy as previously thought," says researcher Heribert Schunkert of the University of Regensburg in Germany.
About 10 percent of any population suffers from white-coat hypertension. Doctors believe that it represents a person's tendency to exaggerate his or her responses to mildly stressful situations. For example, a person with white-coat hypertension may develop spikes in blood pressure while driving, talking on the phone, or in other common situations.
This isn't the first time that researchers have suggested that white-coat hypertension may pose a risk. Research by Stevo Julius of the University of Michigan Medical Center in Ann Arbor and his colleagues suggests that people with white-coat hypertension may have a number of risk factors for atherosclerosis, the condition in which fatty plaque builds up on artery walls.
Julius and his colleagues published a study in the Dec. 16, 1990 Hypertension showing that people with white-coat hypertension tend to suffer from obesity and have high concentrations of an unhealthful fat in the bloodstream. Although these people are outwardly healthy, this constellation of factors puts them in line for a heart attack.
Julius and his colleagues concluded that people with transient hypertension resemble people who exhibit borderline hypertension. The latter show slightly elevated blood pressure that never abates. Research suggests that borderline hypertension poses a cardiovascular risk.
The new research by Schunkert and his colleagues supports the notion that people with white-coat hypertension face an elevated heart-disease risk. Schunkert's team began the study by drawing on a pool of 1,677 mostly healthy men and women who live in and around Augsburg, Germany.
The researchers wanted to determine each person's blood pressure in a relaxed setting. A technician wearing street clothing and no white coat talked to each recruit for at least half an hour in a room with an armchair and a table.
The technician took several blood pressure readings during this meeting. Next, the team subjected each recruit to echocardiography, a technique that bounces sound waves off the heart. The resulting picture reveals abnormalities in the heart's structure or function.
After the test, study subjects waited in a medical exam room for a cardiologist. The doctor, who wore a white coat, took a final blood pressure reading.
People in the study were classified as having normal blood pressure if they had readings of less than 140 millimeters of mercury (mm Hg) systolic and 90 mm Hg diastolic measured by a technician and less than 160/95 mm Hg measured by a doctor. Participants had white-coat hypertension if they had readings of less than 140/90 mm Hg measured by the technician and more than or equal to 160/95 mm Hg taken by the physician. The researchers found that 8 percent of women and 11 percent of men fit this definition of white-coat hypertension. …