NEW YORK, Jan 26 (Reuters Health) - Many people--and their doctors--believe that headaches signal a rise in blood pressure. But a new study from Brazil demonstrates that this belief is probably false.

Among 76 patients with mild hypertension (high blood pressure) whose blood pressure was monitored for a full day, 25 (33%) developed a headache. But the 24-hour blood pressure recordings on these patients showed no change in blood pressure when headache occurred. There were no major differences in blood pressure curves between patients who did and did not have headaches.

Among patients with headaches, eight experienced migraine-like headaches. The rest had tension-type headaches. In their report, published in the January issue of Archives of Internal Medicine, the researchers note that the small number of migraine patients included in the study makes it impossible to interpret the relationship between blood pressure and migraine conclusively.

The one major difference between those who did and did not suffer headaches was that people with headaches had higher blood pressure levels when the device to measure their blood pressure--a cuff worn on the arm--was put on and removed.

This may have been due to an "exaggerated alert reaction," Dr. Miguel Gus and colleagues from the Hospital de Clinicas de Porto Alegre in Brazil, noted. "Anxiety could be the common mechanism to explain the occurrence of headache and the alert reaction in these patients."

One limitation of the study, the authors note, is that it did not include people with normal blood pressure or those with severe high blood pressure.

The researchers point out that some medical textbooks and review articles still state that headache is a symptom of hypertension. "The inconsistency in the literature about the relationship of these two prevalent situations, hypertension and headache, has created some myths among patients," Gus and colleagues write. One such belief is that people can use their own symptoms--including headache--to gauge whether their blood pressure is high.

"In conclusion, our findings show that in patients with mild hypertension there is no association between headache, classified as tension-type or migraine-like, and blood pressure. Health professionals must discourage patients with hypertension from believing that they can rely on the presence of such a symptom to know about their blood pressure levels," the researchers conclude.

SOURCE: Archives of Internal Medicine 2001;161:252-255.
　　From Reutershealth.com