Over The Line

Doctors have warned about the dangers of high blood pressure for nearly a century, ever since U.S. brain surgeon Harvey Cushing and others noted that measuring blood flow was a good way of determining how much stress the heart was under. But exactly what physicians mean by "high" has shifted over the years. Now it appears that the danger point may be lower than previously thought.

In a paper published last week in the Journal of the American Medical Association, the University of Michigan's Dr. Stevo Julius reported that even people with "borderline" hypertension may sustain damage to their heart and blood vessels. Such patients, argued Julius, should seek more aggressive blood-pressure treatment to lower their risk. Dr. Michael Horan, associate director of cardiology at the National Heart, Lung, and Blood Institute, agreed: "The message is that borderline patients should no longer be neglected. These people could already be in trouble."

The definition of borderline is not clear-cut. In general, scientists see blood pressure as a continuum: the higher the reading, the greater the risk of stroke and heart disease. But for practical purposes, doctors often set a cutoff point at 140/90, urging patients whose pressure is above that level to seek treatment. (The 140 is a measure of systolic pressure, the maximum force with which the heart expels blood; the 90 indicates diastolic pressure, the strength of blood flow between beats.) But in this study of nearly 1,000 patients, the researchers found that even people with a mean blood pressure of 130/94 already showed the warning signs of cardiovascular problems. The muscle in their hearts had become less elastic, and failed to relax completely between contractions.

Horan stressed that these findings do not mean that all patients in this blood-pressure range should immediately start taking hypertension medication, but he did recommend life-style changes aimed at bringing the numbers down. Studies have shown that regular aerobic exercise as well as cutting back on saturated fats and sodium, among other measures, can reduce blood pressure. And, said Horan, if a patient is already at high risk for heart disease, % because of a weight problem or family history, for example, medication may be justified.