Blowing A Gasket

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The sinister thing about hypertension is that most of the creeping harm it does happens without the patient's knowing it. People with malignant hypertension may experience such symptoms as headaches or coldness in the hands and feet, but they also may not. People with less severe hypertension may experience nothing at all until calamity strikes. One of the commonest of those pressure-related disasters is heart attack. The higher pressure climbs, the harder the heart has to pump to push the blood. Like any other muscle called on to do more work, the heart responds by enlarging, chiefly in the left ventricle, which is its main pumping chamber. Increased muscle mass is fine in the biceps, but it's bad in the heart, which must be lean and flexible to work as it should. Worse, if a person with hypertension has high cholesterol, the deteriorating condition of vessel walls creates rough spots that serve as toeholds for circulating fats. As fat collects into plaques, they can break free, particularly if vessels are repeatedly being slammed by blood rushing out from the overworked heart. Breakaway plaque can lead quickly to a heart attack.

The brain can take a bad hit too in the form of stroke. About 75% of strokes are caused by a blood clot or loose plaque racing through the system and lodging in the vessels of the brain, where it cuts off the flow of oxygenated blood. Other strokes are essentially hemorrhages, ruptures in brain vessels that give way under elevated pressure.

Scientists studying Alzheimer's disease have also uncovered a possible link to uncontrolled blood pressure. When they scrutinized the brain vessels of people who had died of Alzheimer's, they found that those with a history of hypertension during middle age had tiny changes that did not appear in healthy individuals. "The question is, Where do the micro changes come from--longstanding hypertension or high cholesterol?" says Dr. Richard Mayeux, co-director of Columbia University's Alzheimer's research center, who is studying the connection. If either of them turns out to be involved, controlling both may be an unexpected way to reduce dementia risk.

With that surprising exception, the basic health issues associated with hypertension have not changed. What's new is how deep the pool of at-risk people has become and how serious the danger for them is. The National Heart, Lung and Blood Institute (NHLBI) estimates that of 65 million hypertensive Americans, nearly 20 million are not aware they have the condition. Worse, the 65 million figure is just an estimate of the vulnerable population, and that population is a constantly moving target. Every time the nation's obesity needle ticks upward, the number of hypertensive Americans does too.

What's more, the closer experts look at how doctors actually diagnose high blood pressure, the more they think they've been grading on a too generous curve. Traditionally, readings between 120/80 and 140/90 have been labeled borderline, less likely to require drugs or other intervention. Now the NHLBI believes that patients may begin approaching danger when their systolic reading--the first number--is as low as 115. Although pressure varies from moment to moment and day to day, a reading that hits the danger zone on two separate visits to the doctor may signal trouble.