Dehydration Headache

What is a dehydration headache?

A dehydration-related headache happens when your body doesn’t get enough fluids. Even mild dehydration can cause a headache. Usually, other symptoms of dehydration (such as fatigue, dizziness, extreme thirst and dry mouth) appear along with headache pain.

Dehydration headaches often get better with at-home remedies like drinking water, resting and taking over-the-counter pain relievers. If you have signs of severe dehydration (such as confusion or dizziness), get medical help right away.

How common are dehydration headaches?

Nearly everyone gets a headache from time to time. Headaches are the most common type of pain. They result from many different conditions, disorders and diseases, including dehydration.

Healthcare providers aren’t sure how many people get dehydration headaches. In the United States, most people don’t get enough fluids, either from their food or by drinking water. Lack of fluids can lead to dehydration, which causes headaches. Babies, young children and older adults have a higher risk of dehydration. People with certain health conditions (such as diabetes) also have an increased risk.

What does a dehydration headache feel like?

Pain from a dehydration headache can range from mild to severe. You may feel pain all over your head or in just one spot, such as the back, front or side. The pain is usually like a dull ache, but it can also be sharp.

You may have a throbbing (pounding) headache, or the pain might be constant. The pain might get worse when you bend over, shake your head or move around.

Other dehydration symptoms usually occur along with headache pain. These include:

• Dark urine (pee) and a decreased need to urinate.
• Dizziness and confusion.
• Dry mouth.
• Fatigue.
• Heat cramps (muscle cramps).
• Loss of appetite.
• Passing out or fainting (syncope). This happens in severe cases of dehydration.
• Intense thirst (although you may not feel thirsty at all).
• If your child has a headache along with signs of dehydration, call your healthcare provider right away. Symptoms of dehydration in babies and children include fewer trips to the bathroom (or fewer wet diapers), pale skin and weakness or lethargy. It’s essential to get medical help immediately.

What is dehydration?

Your body is mostly made of water. It’s in your blood, organs, soft tissues and bones. When you sweat and urinate, your body loses fluids and electrolytes. Electrolytes are minerals that help your body work like it should.

Dehydration happens when the amount of fluid that’s leaving your body (in sweat and urine) is more than the amount of fluid you’re taking in. Dehydration can be dangerous because it means your body isn’t getting the fluids it needs.

Dehydration can result from:

• Diarrhea and vomiting.
• Lack of adequate water intake.
• Drinking too much alcohol, which can cause a hangover.
• Heavy sweating from exercise, physical activity or heat. Exercising in higher altitudes also increases the risk of dehydration.
• Some medications, such as diuretics (water pills) to treat heart failure and other conditions. Water pills help your body get rid of excess fluid and salt.

What causes a dehydration headache?

When you’re dehydrated, your brain and other tissues in your body shrink (contract). As your brain shrinks, it pulls away from the skull, puts pressure on nerves and causes pain.

Even mild dehydration can lead to a headache. When you drink water and other fluids, the brain plumps up to its previous size and the pain goes away.

How do I know if I have a dehydration headache?

There are many different types of headaches. Some headaches (like migraines and tension headaches) have no known cause. Healthcare providers call these primary headaches.

Dehydration headaches are secondary headaches because providers know what causes them. You probably have a dehydration headache if:

• Headache pain goes away or gets better with water and rest.
• Pain is only in your head (other types of headaches can cause pain in the neck or shoulders).
• You also have other symptoms of dehydration.

If your headache doesn’t get better after drinking water and resting, see your provider for a checkup. Another condition or illness may be causing your headache. Your provider may order imaging studies (like an MRI or CT scan) to see pictures of your brain and determine what’s causing the pain.

How do I manage dehydration headaches?

Most dehydration headaches get better in a few hours with at-home treatments. To relieve pain from a dehydration headache, you should try headache remedies such as:

• Fluids: Take small sips of water. Drinking too much water too quickly can make you feel sick to your stomach. You can try sucking on ice cubes if you have an upset stomach. Electrolyte drinks (sports drinks) can also replace fluids. But they usually contain high levels of sugar, so only drink them in moderation or choose one with no added sugar.
• Rest: Take a break from physical activity. If you’re in the heat or sun, try relaxing in a cool, shady place. Give your body time to rest.
• Pain relievers: Over-the-counter nonsteroidal anti-inflammatory drugs can provide headache relief. Some headache medicines have caffeine. Avoid these medicines, since caffeine can make dehydration worse.
• Ice: Applying a cold compress to your head can relieve pain. You can also wet a washcloth with cold water and place it on your forehead.

People who are very dehydrated may need additional care. Some people may need to stay in the hospital while they’re recovering. Healthcare providers treat severe dehydration with IV fluids (through a vein in the arm).

How do I prevent a dehydration headache?

The best way to avoid a dehydration headache is to stay hydrated. To prevent dehydration, you should:

• Drink plenty of fluids: Carry water with you when you leave home, and take sips throughout the day.
• Hydrate before you feel thirsty: Drink fluids throughout the day. Don’t wait until you feel thirsty. If you wait until you’re craving water, you’re already a little dehydrated. People who are older might not feel thirsty at all because you can lose your sense of thirst as you age.
• Replace the fluids you lose: When you’re exercising or doing physical activity, take water breaks often. During some sports (like swimming), you may not notice how much you’re sweating. Drinking fluid throughout the day prior to participating in a sport is also helpful.
• Take a break when you need to rest: Listen to your body. If you feel tired or dizzy, take a water break.
• Watch the heat: If you’re outside on a hot day, drink extra water. Rest often, and find a way to stay cool in hot weather.

What is the outlook for people with dehydration headaches?

Most dehydration headaches get better after drinking water and taking it easy for a while. If headaches keep happening, you may have chronic (long-term) dehydration. Chronic dehydration can lead to serious medical problems, including kidney stones and urinary tract infections (UTIs). People who aren’t hydrated have a higher risk of heat exhaustion and other heat illness.

Dehydration can trigger (cause) a migraine headache. If you get migraines, it’s essential to drink plenty of water. Staying hydrated may help you prevent a migraine attack.

When should I see my healthcare provider about a dehydration headache?

See your healthcare provider if:

• Headache pain doesn’t get better: If you still have a headache after drinking water, resting and taking over-the-counter pain medications, call your healthcare provider. Most dehydration headaches get better after a few hours of water and rest.
• Pain comes back or is severe: Call your healthcare provider if your pain returns. Chronic (recurring) headaches and severe pain may be a sign of a serious health condition.
• You have other symptoms: Vision problems, dizziness, nausea and vomiting can be signs of a serious condition. See your healthcare provider if you have these symptoms, along with headache pain that doesn’t go away.
• You have signs of severe dehydration: Dehydration can also lead to serious health problems. If you or your child has signs of dehydration, see your healthcare provider right away.

A note from Cleveland Clinic
Dehydration headaches can range from mildly annoying to severely painful. But they usually go away after drinking water and relaxing in a cool place. To prevent a dehydration headache, drink water throughout the day and increase the amount you drink when you exercise. Always stop and drink water if you feel symptoms of dehydration. If your headache doesn’t go away with water and rest, call your healthcare provider. Get help right away if you have a severe headache or if your pain comes back.