For the past 25 years, doctors in the U.S. have warned their patients about the dangers of high blood pressure, a generally symptomless condition that increases the risk of heart disease, kidney failure and stroke. By aggressively treating folks whose readings exceed the normal limit of 140/90 mm Hg at rest, physicians have prevented millions of premature deaths and untold suffering. But it looks as if we've stopped getting the message. A national health survey released two years ago showed that blood-pressure rates are no longer falling; at the same time, the incidence of stroke has started to rise.
The biggest...