What Is a Dehydration Headache? Recognizing the Signs

Have you ever experienced a headache because you didn't drink enough water? Maybe you were ill, sweating profusely, or could not access enough fluids. Or perhaps you were so engrossed in a task you forgot to drink. After some time, you may have felt a pounding sensation in the head that you may relate to dehydration. Understanding how to prevent and treat dehydration may help you make better choices for hydration and overall health, potentially avoiding headaches.

What is a dehydration headache?

Your body — and your brain — are mostly water. When the body loses more water than it takes in, this can lead to dehydration.

Although dehydration can be associated with headaches, the underlying mechanism is not entirely understood. The brain doesn't have pain receptors, but structures around the brain, like the meninges, do. Headaches can happen when pain-sensitive nerve endings around the head and neck, called nociceptors, are activated by various triggers, such as stress and bright lights. Nociceptors send pain signals to the brain, resulting in the sensation of a headache. For some people, this trigger can be dehydration.

Conversely, the headache itself may not be caused by dehydration. There may be other causes, such as a tension headache from stress or a headache due to sinusitis. If you believe you have a dehydration-related headache, it's important to recognize other dehydration symptoms so you can get the proper treatment.

Symptoms of a dehydration headache

Dehydration headaches are not considered primary; they are regarded as main medical problems not caused by other conditions. Instead, dehydration may trigger primary headaches, such as migraines. Because the headaches caused by different conditions may vary, symptoms of a dehydration headache may not be the same for each person.

The key is to look for the other symptoms of dehydration, which can range from mild to severe and may also differ between adults and children.

Common dehydration symptoms

For adults, common dehydration signs and symptoms may include:

• Increased thirst
• Dry mouth or cracked lips
• Dark-colored urine
• Sweating or urinating less than usual
• Feeling tired

Severe dehydration symptoms

Without treatment, the symptoms can worsen. Severe symptoms may include:

• Confusion or mental fog
• Fainting
• No urine
• Rapid heartbeat and breathing
• Symptoms of shock, including pale skin and cool extremities

For infants and young children

If your child complains of a headache in addition to the following dehydration symptoms, contact your health provider immediately.

• Dry diapers for three or more hours
• Sunken eyes
• Crying without tears
• Dry mouth and cracked lips
• Unusually drowsy or irritable
• High fever

How to recognize a dehydration headache

A dehydration headache may be difficult to differentiate from other headache disorders. For example, if you have a history of migraine attacks, a dehydration headache may come with a preceding aura. However, there are other ways to recognize a dehydration headache.

Key characteristics

Two of the defining characteristics of dehydration headache include:

• Experiencing headache relief within a few hours after rehydration
• Recurring head pain with repeated dehydration episodes

Possible causes

The triggers for a dehydration headache are related to the lack of fluid intake or too much fluid loss. These may include:

• Prolonged periods without drinking fluids
• Excessive sweating, overexposure to heat, or fever
• Intense physical exercise without rehydration
• Illnesses leading to fluid loss, such as vomiting and diarrhea
• Certain medications, such as diuretics, which increase urine output

How to treat and prevent dehydration headaches

Even mild dehydration can trigger headaches. If you have experienced a dehydration headache, there are steps to prevent and treat it.

Short-term treatment

Treatment may consist of things you can do at home. If you start to feel a headache coming, try the following:

1. Drink water slowly to rehydrate. Drinking too quickly or too much may make you feel sick.
2. Rest in a cool place. You can also try applying a cool compress to your forehead.
3. Consider electrolyte beverages if dehydration is due to excessive sweating, vomiting, or diarrhea. Many electrolyte drinks have high sugar content, so consume them in moderation.
4. Pain relievers such as nonsteroidal anti-inflammatory drugs (NSAIDs) may provide relief, but speak with your healthcare provider to see if you have any contraindications.
5. Oral rehydration solutions are available for children over the counter. However, if you suspect that your child is dehydrated, consult with the pediatrician first.

Sometimes, you may need additional care if the symptoms of dehydration do not resolve. Very dehydrated people may need to stay in the hospital and receive intravenous fluids.

Long-term prevention

For healthy individuals, dehydration headaches can be preventable. Steps to prevent dehydration include:

1. Drinking enough water. The general advice may be to drink water until your urine is pale yellow, but each individual has different needs. For example, a person with heart failure or kidney disease may have fluid restrictions. It's best to consult with your healthcare provider regarding your condition.
2. Increase fluid intake when engaging in physical activity, the weather is hot, or you are sick.
3. Avoid excessive caffeine, sugary drinks, and alcohol, which can actually make you feel more thirsty and urinate more often.

Who is at risk for dehydration headaches?

Some people are more vulnerable to dehydration, which may trigger headaches. These include:

• Infants and young children prone to illnesses causing vomiting and diarrhea
• Older adults with diminished thirst sensation and less bodily reserve
• People who work in dry, hot weather or engage in high-intensity sports
• People with chronic illnesses, such as diabetes or cystic fibrosis that may make them sweat or urinate more
• People who take medications that can increase urination or sweating, such as diuretics and certain antidepressants

When to seek medical help

If your headaches recur frequently or persist despite rehydration, it may be a sign that you need to seek medical help. The healthcare provider may check to see if your electrolyte levels are within normal limits or if you have an underlying medical condition. If you feel that your headache is worsening and suspect symptoms of severe dehydration, you will most likely need emergency medical care.

Remember that headaches may be caused by other medical conditions, such as a stroke. If you have a sudden, severe headache and other symptoms of a stroke, call 911.

Final word

Drinking water may seem simple, but proper hydration can help the body function well. This can also prevent dehydration-related headaches. Remember to drink enough fluids, especially during exercise, illness, or hot weather. Be mindful of common symptoms of dehydration for yourself and your loved ones, and seek medical care when appropriate. With proper strategies, you may be able to prevent dehydration headaches and increase your level of well-being.