Dehydration Headache: Causes, Symptoms and Remedies.

Is a pulsing headache a familiar feeling?

Rather than reaching straight for over-the-counter medication, you might want to consider the cause of your discomfort first. Headaches typically feel different depending on what has triggered them, which could be of a variety of factors - all of which should be taken into consideration when treating them.

One common trigger for headaches is dehydration, as it often sneaks up on people.

What Is Dehydration?

According to the NHS (Dehydration symptoms and treatments, 2021), dehydration is caused by not drinking enough fluid or by losing more fluid than you take in. Fluid is lost through sweat, tears, vomiting, urine or diarrhoea. Despite the daily recommended intake of water, somepeople are not able to maintain enough water in their bodies, whether due to illness, extreme physical exertion, overexposure to the sun or other causes.

Dehydration occurs when the body loses water and crucial electrolytes - like sodium and potassium - which aren’t replaced. Depending on your age, weight and the amount of lost fluid, you can experience mild to severe dehydration.

People often don’t feel thirsty until after they’re already dehydrated. According to the NHS, feeling thirsty or having dark-coloured urine are two early signs of dehydration. This is the body's attempt to increase water intake and decrease water loss.

In addition, other symptoms may include:

  • dizziness or light-headedness
  • headaches 
  • tiredness
  • dry mouth, lips and eyes
  • passing small amounts of urine infrequently

In babies, signs of dehydration can include:

  • a sunken soft spot on their head
  • few or no tears when they cry
  • a dry mouth
  • fewer wet nappies
  • dark yellow urine
  • drowsiness
  • fast breathing
  • cold and blotchy-looking hands and feet

To help combat dehydration – especially in children, infants and babies, the NHS advises diluted squash or a special electrolyte rehydration solution. 

Why Dehydration Can Cause Headaches?

The importance of water to our bodies is often underestimated. Your body can’t function properly without enough water. Both physical and cognitive abilities are negatively impacted by dehydration. Research carried out at Cambridge University (Effects of hydration status on cognitive performance and mood, 2014) suggests that particular cognitive abilities and mood states are positively influenced by water consumption, and that the impact of dehydration on cognition and mood is particularly relevant for those with poor fluid regulation.Even mild dehydration can impair cognitive performance. 

According to the researchers, “Despite water constituting 60–80 % of the human body, it is often overlooked as a significant nutrient that can affect not only physical performance, but also mental performance.” Water is just as critical to the brain. When we don’t consume enough fluids, our brains can start to shrink from fluid loss. This causes the brain to pull away from the skull, which triggers pain in the meninges, the membrane that surrounds the brain.

Symptoms of a Dehydration Headache.

So how do you know when your headache is caused by dehydration? 

Headaches are a common symptom of mild to moderate dehydration. In fact, many types of headaches, including migraines, can be triggered by dehydration. Health line (O'Keefe Osborn, 2019) reports: “A small survey published in the medical journal Headache found that among the people interviewed, 1 in 10 had experienced a dehydration headache. These respondents described the headache as an aching that got worse when they moved their heads, bent down, or walked around.” 

A dehydration headache typically won’t include pain in the back of the neck as with a tension headache or pressure in the face as with a sinus headache. Instead, it’s commonly described as a pulsating pain on both sides of the head.Dehydration headache symptoms also include other general symptoms of dehydration listed above.

How to Get Rid of a Dehydration Headache.

Because dehydration headaches occur due to lack of water in the body, short-term fixes involve consuming more fluids.

Drink Water. It is reported by many sources that most dehydration headaches are relieved within three hours of drinking a glass or two of water. Drinking too fast can sometimes cause vomiting, so take slow sips.

Drink Electrolyte Rehydration Solutions. Consuming an electrolyte rehydration solutions is taking a giant step further to supporting your body’s hydration. A rehydration solution contains the right mix of electrolytes, sugar and water to help rapidly replenish lost fluids.

Electrolytes are minerals your body needs to survive. They regulate nerve and muscle function, balance blood pressure, help build new tissue and much more. Dehydration can disrupt your body’s electrolyte balance. A low-sugar, electrolyte-rich drink like Hydralyte can help to rehydrate you more quickly and effectively than water alone because it replaces these important minerals.

Once rehydrated, your brain returns to its normal state, relieving your headache.

Preventing Dehydration Headaches 

Rather than reacting to it or being forced to resort to over-the-counter medication, the best way to avoid the pain of a dehydration headache is to prevent it. How? By drinking plenty of fluid every day.

In addition, if you’re prone to dehydration or find it difficult to stay hydrated on water alone, try consuming an electrolyte rehydration solution like Hydralyte. The NHS (Dehydration symptoms and treatments, 2021) also recommend an electrolyte solution for those who do not find relief by just drinking water. These solutions can help whether you’re running around before work or school in the morning, taking part in exercise or recovering from a bout of the flu.

Hydralyte’s formula contains the correct balance of glucose and electrolytes for quick rehydration. It has four times the number of electrolytes, as well as 75% less sugar than leading sports drinks. It’s also hypotonic, which is the most rapidly absorbed fluid type for rehydrating the body’s cells.

We strongly advise that while dehydration headaches can be easily treated, the best way to avoid the pain is by actively staying hydrated at all times.


Inform, N., 2021. Dehydration symptoms and treatments. [online] Available at: <> [Accessed 20 September 2021].

Cambridge University Press. 2014. Effects of hydration status on cognitive performance and mood. [online] Available at: <> [Accessed 20 September 2021].
O'Keefe Osborn, C., 2019. Dehydration Headache: Symptoms, Remedies, and Prevention. [online] Healthline. Available at: <> [Accessed 20 September 2021].