The researchers also looked at another measurement, called the pulse pressure, or the change in blood pressure when the heart contracts. It's computed by subtracting the diastolic reading (bottom number) from the top.
Those with higher pulse pressure had up to a 50 percent reduction in the number of headaches.
Further research may hold clues that would help headache sufferers. "We would like to examine whether there are any common pathways in the autonomic nervous system with regard to blood pressure regulation and headache, and whether it also can be demonstrated on an individual level," Tronvik said.
The results make sense to another expert, Dr. Nabih Ramadan, a staff physician at the Diamond Headache Clinic, in Chicago.
"The higher the pulse pressure," he explained, "the stiffer the blood vessel is going to be. The stiffer the blood vessel, the less likely the nerve endings are activated. The less likely the nerve endings are activated, the less likely you will get headache."
The study has weaknesses, Ramadan said. Among them: Pulse pressure is a very crude measurement and, as the authors noted, it was unknown whether participants were on blood pressure medicines for high blood pressure or for headaches.
Ramadan emphasized that those with high blood pressure need to be treated to bring the level down.
To learn more about migraine, visit the National Headache Foundation.
SOURCES: Erling Tronvik, M.D., researcher, Norwegian National Headache Center, Trondheim University Hospital, Trondheim, Nor
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