For many years headaches were thought to be triggered by elevated blood pressure.  Evidence had suggested that only very sudden increase in blood pressure triggered a headache in some patients, but the myth of high blood pressure headaches has persisted.  Norwegian researchers published a very surprising finding in the April issue of journal Neurology.   They looked at the data on 120,000 people and found that increasing systolic blood pressure was associated with a decrease in migraine and non-migraine headaches.  Even more striking was the inverse correlation with the pulse pressure (difference between systolic and diastolic pressure, for example blood pressure of 110/80 means that the pulse pressure is 30).  Patients with higher pulse pressure had fewer migraine and other headaches.  It can be speculated that hardening of arteries that occurs with elevated blood pressure makes them less likely to constrict and dilate, which is part of a migraine process.