A migraine headache, or any type of pain for that matter, can cause your blood pressure or heart rate to go up temporarily. So while severe high blood pressure can cause headaches, it's much more likely to be the other way around -- a single elevated blood pressure reading that's triggered by a headache. Your blood pressure should go back to normal after the headache resolves.
Migraines should not cause persistently elevated blood pressure readings. Most doctors won't diagnose hypertension until you have two or more elevated readings over several weeks. They will also discard elevated readings that occur while you are anxious, ill, or stressed, or that are measured within about 30 minutes of a cup of coffee or cigarette.
It's worthwhile to note one other link between migraines and high blood pressure: While blood pressure drugs such as beta blockers and calcium channel blockers may be used to prevent migraines, they don't work by lowering the blood pressure. Instead, they appear to reduce spasm in blood vessels that surround the brain. These drugs will help to prevent migraines equally well in people who do and don't have underlying high blood pressure.
