Dehydration Headache

What is a dehydration headache?

A dehydration headache is a symptom of dehydration that happens when your body isn’t getting enough fluids.

The pain in your head is usually just a sign that you need to take it easy and have some water. Don’t ignore signs of dehydration. And go to the emergency room if you’re experiencing severe symptoms like confusion or dizziness.

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, like at the back, front or side. The pain usually feels like a dull ache, but it can also be sharp or stabbing.

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

You might experience other dehydration symptoms like:

• Appetite loss
• Darker than usual pee
• Dry mouth
• Fatigue
• Intense thirst (but some people with dehydration don’t feel thirsty at all)
• Muscle cramps
• Peeing less often than usual

Visit a healthcare provider right away if your baby or child has a headache along with other signs of dehydration, including:

• Pale or lighter than usual skin
• Peeing or pooping less (or fewer wet diapers)
• Weakness or lethargy

How can dehydration cause headaches?

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

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

What are the complications?

If you have a dehydration headache, you might be more likely to develop a migraine. And dehydration increases your risk of heat exhaustion and other heat-related illnesses.

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).

How do I know if I have a dehydration headache?

There are a lot of different types of headaches. It can be hard to tell which one you have, especially when you’re trying to puzzle it out with an already achy head. Some headaches (like migraines and tension headaches) have no known cause. Healthcare providers call these primary headaches.

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

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

Visit a healthcare provider if the headache doesn’t get better after drinking water and taking a break from physical activities for a few hours. They’ll help you understand what’s causing the headache and what you can do to treat it.

You probably won’t need tests for a provider to diagnose a dehydration headache. They can usually tell what it is based on the symptoms you’re experiencing. But they may use imaging tests like an MRI or CT scan to take pictures of your brain if they think you might have a more serious issue.

How do I manage dehydration headaches?

Most dehydration headaches get better in a few hours with at-home treatments. The best ways to get rid of a dehydration headache include:

• Fluids. Getting hydrated again is the fastest way to treat a dehydration headache. But take small sips of water. Gulping too much water super 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 a lot of sugar, so try to choose one without any added sugar. Avoid energy drinks and anything with caffeine. Drinks with caffeine can be safe in small amounts. But they can make dehydration worse if you’re already experiencing symptoms like a headache.
• Rest. Give your body time to recover. Take a break from physical activity. If you’re in the heat or sun. Try relaxing in a cool, shady place.
• Pain relievers. Over-the-counter NSAIDs can help relieve headache pain. But avoid any headache medicines that have caffeine. It can be a surprisingly common ingredient.
• Ice. Putting an ice pack or cold compress on your head can help you feel better. Wrap ice packs in a thin towel to avoid putting them directly on your skin. You can also wet a washcloth with cold water and place it on your forehead.

You might need other treatments if you have severe dehydration. A provider may give you an intravenous (IV) infusion of fluids.

How do I prevent a dehydration headache?

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

• Avoid alcohol and caffeine. Alcohol and caffeine are both diuretics (they make you pee more). This can make it hard to stay hydrated, especially on a hot day or when you’re sweating more than usual.
• Check your pee. Your pee is one of the fastest ways to check your hydration level. If it’s clear, pale or straw-colored it’s OK. If it’s darker than that, drink some fluids.
• Drink plenty of fluids. Carry water with you when you leave home, and take sips throughout the day. Aim to drink six to eight glasses of water per day. That’s around half a gallon (between 1.5 and 2 liters).
• Replace the fluids you lose. When you’re exercising or doing physical activity, take water breaks often. You may not notice how much you’re sweating during some sports like swimming. Drinking fluid throughout the day prior to participating in physical activity is also helpful. If you’re sweating a lot, you may want to drink something like a low-sugar sports drink to replace the electrolytes you’re losing.
• Take a break when you need to rest. Listen to your body. If you feel tired or lightheaded, take a water break.
• Watch the heat. If you’re outside on a hot day, drink extra water. Rest often, and try to stay cool in hot weather.

How long does it take to recover from a dehydration headache?

A dehydration headache usually lasts a few hours. It should get better and go away after you pause activities and have some water. Taking pain medication may help you feel better sooner, but it’s still important to get and stay hydrated. That’s the only way to treat the dehydration that caused the headache.

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

See a healthcare provider if the pain from a dehydration headache lasts more than a few hours after you drink some water. Visit a provider if the pain comes back later (recurs) or you can’t manage it with at-home treatments.

When should I go to the emergency room?

Go to the ER if you have a headache and any symptoms of severe dehydration, including:

• Confusion
• Dizziness
• Nausea and vomiting
• Passing out or fainting
• Rapid heart rate (faster than 120 beats per minute at rest in adults)
• Vision problems

Which questions should I ask my healthcare provider?

• Do I have mild or severe dehydration?
• How much water should I drink every day?
• When is it safe for me to resume physical activities?
• Which changes or other symptoms should I watch out for?