The pendulum has swung back and forth on the connection between hypertension and headaches. A study finds they could be related.

Sometimes a headache throbs just as they show in pain-reliever ads. Other times, it feels like your head is going to explode from the pressure within. With symptoms like these, it certainly seems like high blood pressure, and all that extra pounding of blood against vessel walls, could make someone’s head hurt.

A cerebral symptom

Dr. Theodore C. Janeway, who went on to become the first full-time professor of medicine at Johns Hopkins, proposed a connection between headaches and high blood pressure, also known as hypertension, way back in 1913. In a famous article in the Archives of Internal Medicine, Dr. Janeway analyzed the 870 patients with high blood pressure whom he and his father had seen over a nine-year period.

We tend to think of medical knowledge as being all freshly minted, but Dr. Janeway made observations 90 years ago that still ring true: High blood pressure increases the risk for death from cardiovascular causes, it may damage the kidneys and the eyes, and it’s more common among people who have diabetes.

Dr. Janeway identified headaches as the main “cerebral” symptom of high blood pressure, and described them as coming on in the morning or waking the patient up and then going away during the course of the morning.

Theory debunked

Despite the staying power of many of his conclusions, the conventional wisdom is that Dr. Janeway got it wrong when it came to headaches and high blood pressure. One classic study pointed to the power of suggestion: When people with high blood pressure were told about the condition, they reported having more headaches than those who were kept in the dark about their condition. Epidemiologists who have explored the issue haven’t spotted the kind of associations that hint at cause-and-effect relationships. For example, Norwegian researchers published a study that followed about 23,000 adults in one county in the country for more than a decade. They found that people with high systolic (the top number) blood pressure at the beginning of the study actually had fewer headaches than those with a lower reading. The headline for an accompanying editorial asked ruefully, “Why does the hypertension headache myth persist?”

The comeback

But hold on. Consider the results reported by British researchers in the Oct. 11, 2005, issue of the journal Circulation. Their study was a meta-analysis (combining and reanalyzing other studies) that combined previously published results from 94 randomized, placebo-controlled studies of four different classes of blood pressure–lowering drugs (thiazide diuretics, beta blockers, ACE inhibitors, and angiotensin II receptor blockers). Their data included about 17,600 patients who’d been treated with a drug and about 6,600 who were randomly assigned to take a placebo. The conclusion? Those who took hypertension drugs were a third less likely to be bothered by headaches than those who took a placebo.