Ask the Doctor Q&A: Dehydration and Headaches
Question:
Can dehydration cause headaches?
Answer:
Yes, insufficient water intake can cause headaches. Some people are much more prone to headaches related to dehydration than others. Those who are more susceptible learn to avoid the headaches by making sure they drink enough fluids daily.
Water-deprivation headache can cause pain throughout the head or it can be more localized to the front, back or less often is a one-sided headache. The head pain tends to intensify by bending the head down or other head movements. Even walking can make the headache worse.
The exact cause of dehydration headaches is unknown. The brain itself does not have pain receptors. Dehydration headache is possibly triggered by pain receptors in the lining around the brain, called the meninges. Lower pressure inside the arteries that supply blood to the meninges could stimulate the pain receptors.
Water-deprivation headache caused by simply not drinking enough fluids during the day should respond within an hour or two to drinking 16 to 32 ounces of water. Longer or more severe dehydration will require more fluids and lying down for several hours. If dehydration is very severe and vomiting prevents adequate oral fluid replacement, intravenous fluids may be needed to relieve the headache.
Of note, the headache of migraine attack can be prolonged if the person is not adequately hydrated. Even if you have nausea with a migraine attack, you should try to sip a little fluid every few minutes at the onset of symptoms.
- Added to Medpedia December 2008