Water: good medicine for headache prevention

The golden rule for headache and migraine sufferers is to drink plenty of fluids. 1.5 liters a day is the usual figure quoted. Now that doesn’t mean a beer after work, but non-alcoholic beverages such as tea, water and – in moderation – diluted fruit juices. Adequate fluid intake is essential for the smooth functioning of many vital processes in our body. A lack of water upsets the balance. Problems arise that can take many forms, including headache and migraine attacks. But why, exactly? Time for a deep dive into the matter of water...

Dehydration – when you lose more water than you take in

A British neurologist called Joseph N. Blau coined the term 'water deprivation headache' in 2003. He noticed that headaches can happen if your body does not get the fluids it needs, a state known as dehydration. He also observed that headaches triggered by water deprivation were relieved by fluid intake. Subjects who drank half a liter of water experienced headache relief after an average of 20 minutes. Impaired concentration, dizziness, irritability and pallor were identified in addition to the dehydration-induced headache.

‘Water deprivation headache’ is not a primary headache disorder

The International Headache Society has maintained a list of scientifically proven headache disorders since 1988. This list is a detailed classification of all headache disorders and the criteria used to diagnose each one. Researchers and physicians use this list to distinguish between different types of headache, diagnose patients properly, and give them the treatment they need. Water deprivation headache is not included in this list as a distinct type of headache.

Can dehydration trigger a migraine?

Experts agree that dehydration is a classic migraine trigger. Joseph N. Blau kept up with his research after 2003 and was able to prove two years later that a lack of body water is a major contributor to migraine attacks. More than one-third of the subjects he asked said that not drinking enough was a personal migraine trigger. Later research confirmed this link. Interestingly, dehydration had not been studied adequately before. That was about to change. A more recent study published in 2020 showed that the number and duration of attacks in people with migraine was inversely related to their water intake. Higher fluid intake was associated with fewer symptoms.

A fruitful research field: fasting

The Muslim fasting month of Ramadan provides a very interesting setting for studies on the links between fluid intake and migraine. Muslims who observe the annual fasting period do not eat or drink anything at all between sunrise and sunset. Depending on season and region, daily fasting periods can last 18 hours or more. A study investigating the links was performed in 2010 in a neurological clinic in Israel. The findings were obtained in a predominantly (75%) female patient population. The number of migraine days reported by participants was three times higher during Ramadan than in the control month. The author of the paper sees a clear link with the inadequate fluid intake. He also noted a major reduction in quality of life in affected subjects.

Experts now agree that individuals who drink no fluids while fasting inevitably become dehydrated in the course of the day. Other typical consequences apart from headaches include sleep and mood disorders, irritability and fatigue. In addition, long periods of fasting can disrupt the brain's energy supply. An undisrupted energy supply is crucial for headache and migraine sufferers because it helps prevent attacks.

Even mild dehydration impairs mental performance

Many studies have found that dehydration can have other effects besides headaches. Impaired mental performance is one. Even mild dehydration results in reduced blood flow to the brain. This significantly interferes with the otherwise smooth functioning of processes in the brain. Dehydration is a special risk for older adults. Many old people do not drink the recommended amounts. The associated dehydration can worsen existing weakness, fatigue and confusion.

What happens in your brain if you are dehydrated?

The exact ways dehydration causes migraine and other headache attacks are still not fully understood. One theory is that the lack of water affects certain blood vessels in the brain, resulting in headaches. If the fluid deficit is corrected, the body’s water balance goes back to normal and the headache disappears. Another explanation looks at the blood and the substances dissolved in it. If the substances present in the blood are dissolved in too little fluid, fluid is taken from adjacent brain tissue to make up the missing amount. These processes cause mechanical friction that inflames pain-sensitive meninges and their blood vessels. A headache develops as a result. It is hard to tell at the moment how accurate these two explanations may be. Much more research needs to be done in this area.

Dehydration and headache: a definite link

The exact processes by which dehydration triggers headache and migraine attacks are not fully understood yet. Nevertheless, it is clear from the available studies that a causal relationship exists. Regular and sufficient fluid intake is a cornerstone of headache and migraine prevention. Even mild dehydration has an impact on brain performance. Preventing the slightest fluid deficit is important.

Luckily, help is at hand. If remembering to drink regularly is difficult, regular phone alerts can help remind you. You can use special apps to track your water intake. The 'Prevent-headache.org' app has a feature that allows you to check your drinking habits. You can also set up reminders to drink a specific amount at regular intervals throughout the day. Then you’ll be all set to beat a major pain trigger and reduce your headache burden.