What can cause headaches as a symptom?

Dehydration is a well-known cause of headaches because it affects the body's fluid balance and can lead to a reduction in blood volume. When the body is dehydrated, it can trigger pain receptors, which may result in a headache. Dehydration can also limit the transport of nutrients and oxygen to the brain, contributing to feelings of fatigue and discomfort.

In contrast, while fluid retention can create pressure in various parts of the body, it is not typically linked to headaches in the same direct way. Overhydration can lead to a more serious condition known as hyponatremia, but headaches as a common symptom are less frequently associated with it. Allergic reactions can cause a variety of symptoms, including headaches, but they are generally related to other factors such as inflammation and nasal congestion rather than a direct effect on hydration status. Understanding the mechanisms behind dehydration’s impact on the body highlights its role in the onset of headaches, reinforcing the importance of maintaining adequate hydration.