Dehydration as a Cause of Headaches

Dehydration is one of the factors that can influence the onset or exacerbation of headaches. Although the mechanism by which dehydration affects headaches is not fully understood, data suggest that this condition can impact the pain threshold, intensifying pain and increasing the risk of a range of disorders associated with headaches.

According to the International Classification of Headache Disorders (ICHD-3), dehydration-induced headaches are classified as secondary headaches resulting from homeostasis disturbances. The specific condition "Water Deprivation Headache" (headache caused by lack of water) does not have a separate status in the classification but is of interest for further study, as it is associated with rapid relief after rehydration.

Dehydration increases blood viscosity, raising the risk of thrombosis and potentially triggering headaches. Studies indicate that increased water consumption has a positive effect on migraine patients. For instance, an experiment showed that increasing water intake by 1.5 liters over two weeks helped reduce the frequency of attacks and alleviate pain, although statistical significance was not reached due to a small sample size. Another study observed improved quality of life despite unchanged migraine frequency. Additionally, a link was found between higher water consumption and reduced frequency and severity of migraines in women.

Dehydration and Pain Threshold: Studies have shown that dehydration lowers the pain threshold in healthy individuals. Specifically, experiments using the cold pressor test revealed an increase in pain sensitivity and a reduction in pain threshold in participants who were dehydrated. Functional MRI demonstrated activation of pain networks in the brain, which may indicate neurophysiological changes associated with fluid deficiency. These findings highlight the potential role of dehydration in triggering headaches and increasing their intensity.

Dehydration and Fasting: An analysis of data collected from Iranian hospitals over a seven-year period showed a significant increase in cases of thrombosis during Ramadan, when patients are more likely to experience dehydration due to fasting. This supports the connection between dehydration and an increased risk of thrombosis, which may worsen the condition of patients prone to headaches.

The Impact of COVID-19: During the COVID-19 pandemic, patients with this condition often reported worsening headaches, particularly in cases of dehydration. Studies have shown that increasing water intake may reduce the frequency and severity of such headaches.

Alcohol and Dehydration: While alcohol consumption is often linked to headaches, research indicates that alcohol itself is a trigger, not just dehydration. Even small amounts of alcohol that do not cause significant dehydration can trigger headache attacks. However, adequate water intake can mitigate the negative effects of alcohol on the body.

Dehydration is a significant factor that can exacerbate headaches associated with various conditions. While increasing water intake is not a universal solution, maintaining normal hydration levels may improve the quality of life for patients. Further research is needed to better understand the mechanisms by which dehydration influences headaches and to develop effective strategies for their treatment.