A dehydration headache describes a type of headache that a person may experience when the body loses too much fluid and electrolytes. Replenishing fluids can often treat a dehydration headache.

There are many different kinds of headaches. Headaches are among the most common causes of pain that can negatively affect daily life. At least 9 out of 10 adults will experience one at some point in their life.

Some headaches can be easy to treat and avoid. One of those types is a dehydration headache. This article explores what a dehydration headache is, the signs that indicate a person may have one, and how they might treat or prevent it.

A woman fills up water in the sink to counter a dehydration headache
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A dehydration headache can happen when the body does not get enough fluid. Dehydration headaches can be relatively mild or as severe as a migraine headache.

How dehydration triggers headaches

The body requires a balance of fluid and electrolytes to function properly. Electrolytes are minerals such as potassium or sodium that help regulate different bodily functions. Every day, the body loses water through activities such as sweating and urinating. When this happens, the body also loses electrolytes.

Most of the time, the amount of fluid lost is easily balanced through drinking or eating fluid-rich foods. However, sometimes the body loses water faster than a person can restore the balance. During these times, the body can become dehydrated. This can lead to complications, including dehydration headaches.

When the body is dehydrated, the brain can temporarily contract from fluid loss. This causes the brain to pull away from the skull, causing pain and resulting in a dehydration headache.

Once rehydrated, the brain returns to its usual state, relieving the headache.

A dehydration headache can feel like a dull headache or an intense migraine headache. Pain from a dehydration headache can occur at the front, back, side, or all over the head. Moving the head may cause more pain.

Unlike a sinus headache, a person experiencing a dehydration headache will likely not feel facial pain or pressure. Pain is also unlikely to occur in the back of the neck, as it might with a tension headache.

As dehydration headaches only occur when the body has lost too much fluid, symptoms of dehydration will occur with the headache. These symptoms include:

  • extreme thirst
  • reduced urination
  • dark-colored urine
  • confusion
  • dizziness
  • fatigue
  • dry, sticky mouth
  • loss of skin elasticity
  • low blood pressure
  • increased heart rate

Some people may only experience a dehydration headache if they are severely dehydrated. They may experience the above symptoms as well as additional symptoms, such as:

Dehydration headaches only occur when the body has lost too much fluid. Even mild dehydration can cause a dehydration headache.

Dehydration happens when the body does not get enough water to meet its needs. Certain factors can prevent the body from replenishing fluids and electrolytes.

These factors increase the risk of dehydration and include:

  • diarrhea
  • vomiting
  • extreme sweating, either from heavy exercise or heat
  • fever
  • excess urination

Risk factors for dehydration

Anyone can experience dehydration. Most people will experience mild dehydration. However, some individuals are at higher risk, including:

  • people who live at higher altitudes
  • infants and young children
  • elderly people
  • people with chronic illnesses, such as diabetes and kidney disease
  • people who take medications that increase urine output
  • endurance athletes or people engaging in strenuous physical activity
  • people who live in hot climates

These groups of people should take special care to stay properly hydrated.

The best way to relieve a dehydration headache is to address both the pain and the loss of fluid.

If a person has a dehydration headache, they should:

  • Increase fluid intake by drinking water or other healthy fluids.
  • Suck on ice cubes.
  • Replace lost electrolytes with a sports drink.
  • Temporarily decrease physical activity and avoid heat to reduce sweating.
  • Avoid alcohol and caffeine, which can increase dehydration.

While the above measures may treat dehydration, it can take a while for this type of headache to go away.

A person may take acetaminophen or ibuprofen to help manage the pain.

In certain situations, such as ongoing vomiting or diarrhea, home remedies may not be enough to avoid severe dehydration. A person may need to go to the hospital for intravenous fluid and salt replacement.

People should seek medical care immediately to prevent serious complications, such as:

The best way to prevent a dehydration headache is to avoid dehydration. A person can take the following steps to keep their fluid and electrolyte levels in balance:

  • Drink enough fluid: Most people need at least 8 cups of water per day, though some individuals may need more.
  • Eat fluid-rich foods: Foods such as cucumbers, other vegetables, and fruits have a high water content.
  • Get enough fluid throughout the day: Spreading out the amount of fluid consumed rather than drinking it all at once helps keep the body hydrated.
  • Hydrate more during exercise or exposure to hot weather: During times of heavy sweating, such as during heavy exercise or exposure to hot weather, increase water intake. Drinking more water during these times will replenish the extra fluids lost through sweat.
  • Treat underlying causes of dehydration: Fevers and infections can cause the body to lose more fluid than usual. Addressing the causes of dehydration while increasing fluid intake can help prevent dehydration.
  • Avoid caffeinated beverages and alcohol: Caffeine and alcohol can both increase urine output, leading to a higher risk of dehydration.
  • Reduce strenuous activity during heat or if feeling unwell: Heat and illness can both increase the body’s need for fluids. Heavy exercise can cause extra fluid loss through sweat, which can be dangerous in these situations.

Following these steps should help prevent dehydration headaches.

If a person experiences more than the occasional dehydration headache, they should talk with a healthcare professional to rule out other underlying causes.

A dehydration headache occurs when the body loses too much fluid and electrolytes.

A person can avoid dehydration by drinking enough water, avoiding dehydrating drinks such as coffee and alcoholic beverages, and staying away from excessive heat.

To treat a dehydration headache involves treating the dehydration by replenishing fluids in the body. In some cases, dehydration can be severe and may require hospitalization.