No link between high blood pressure and headaches

Severe headaches are not a sign of high blood pressure, as is commonly thought, finds research in the Journal of Neurology Neurosurgery and Psychiatry. If anything, high blood pressure seems to reduce the risk of these headaches, the study shows.

The findings are based on the blood pressure readings of over 22,000 adults who responded to a survey 11 years later in 1995 to 1997 about headache frequency.

The questionnaire showed that 28 per cent of them suffered repeated headaches, of which migraine headaches were reported by one in four.
High blood systolic pressure readings – above 150/90 mg Hg – tended to be associated with a 30 per cent lower frequency of headache across all age groups. And high blood pressure sufferers had fewer headaches than people with blood pressure readings below 140 mg Hg. The higher the systolic reading the lower the risk of headache.

When the researchers analysed headache by type, they found that high systolic blood pressure (the first number in a reading) was associated with a lowered risk of non-migraine headache, and a lowered risk of migraine in women.

The same was true of diastolic pressure, but there was no clear-cut association with migraine risk.

Excluding people who had high blood pressure for which they were being treated made no difference to the results.

High blood pressure reduces pain sensitivity in the brain and spinal cord, say the authors. This phenomenon known as hypertension associated hypalgesia, may explain why there does not appear to be any link between high blood pressure and headache, they say.