As blood is pumped out of the heart, it creates a force or pressure against the walls of the blood vessels throughout the body. When this pressure is above the normal level of 120/80mm Hg, the condition is called high blood pressure or hypertension. If this pressure reading shoots up to 200/140mm Hg or higher, it may cause internal bleeding of the retinas and swelling of the optic nerves, resulting in the severe pain associated with a blood pressure headache. The combined effects of very high blood pressure readings and what patients describe as “blinding” headache are referred to as malignant hypertension—it is also considered a “silent killer” because it can occur with no warning signs and quickly turn fatal. Although the exact cause of malignant hypertension is still unknown, it has been established that it occurs only in about 1% of the cases dealing with high blood pressure.
Aside from a blood pressure reading that is excessively high, it is also believed that a sudden increase can cause a headache. The pain in this instance is nowhere near as acute as the blood pressure headache typical in malignant hypertension, and a common example would be a morning headache that is caused by the surge of blood when a person stands up quickly after resting. A few other conditions which cause an abrupt rise in blood pressure accompanied by head pain are abnormal increases of certain hormones, side effects of certain prescribed medications, and beverages with alcohol or caffeine. Exposure to physical pain and emotional discomforts can also lead to a blood pressure headache of this type.
Unlike in malignant hypertension, it is still not clear in these cases if high blood pressure causes the headache or if the headache triggers the hypertension. This cause-effect relationship between hypertension and headaches has not been clarified despite numerous attempts over the past century, mainly because the technology to capture these statistics has not been readily available. As a result, a strong headache accompanying a period of hypertension has been labeled as blood pressure headache, even though the scientific proof of this process is still in question.
For example, a Brazilian study claimed to work around the limitations of earlier research, and their published findings to the American Heart Association suggested that there is no connection at all between hypertension and headache. The only exception made in the medical journal was a blood pressure headache caused by extremely high level of blood pressure, which has already been documented as malignant hypertension. As technology continues to expand with new innovations and procedures, more definitive studies should be able to better explain the reason that blood pressure headaches occur.
