Dehydration Headache: Symptoms, Treatment, and Prevention

Dehydration Headache: Symptoms, Treatment, and Prevention

Dehydration  is a common cause of headaches. Fortunately for you, this can easily be prevented by making sure you drink enough water! Read on to find out more about the symptoms of a dehydration headache, as well as how to treat and prevent it (hint: we’ve got just the thing!)

What is a dehydration headache?

Simply put, a dehydration headache is one brought on by not drinking enough water. This can also be exacerbated by drinking alcohol or caffeine when you are already suffering from dehydration. This is your body’s way of telling you it’s not getting the fluids it needs and you’re in need of a huge glass of water, stat!

How does dehydration trigger headaches
Having said that, what is the link between water and headaches? Well, dehydration causes headaches because the lack of water puts pressure on blood vessels and nerves inside the skull and this causes pain when you do any activity that increases blood flow through these blood vessels e.g. exercise. Your brain would typically start to feel dry and itchy before the pain kicks in.


Symptoms of a dehydration headache

The main symptoms of dehydration include:

  • Headaches (especially migraines)
  • Dry mouth or throat
  • Dizziness

One good way to find out: if the pain goes away after drinking water and resting, it’s most likely a dehydration headache. 

Causes of Dehydration Headaches

The top causes of dehydration headaches are heat and physical activity. However, as mentioned before, drinking alcohol and caffeine can also make the situation worse if you are already not drinking as much as you should. These are some situations that could potentially cause dehydration and subsequently, a headache:

  • Heat: If you’re out in the sun for quite some time without taking enough water, your body starts to lose water through perspiration which then leads to dehydration and its headaches.
  • Physical Activity: Losing water through your workout and not replenishing it adequately will lead to dehydration headaches, so keep your Sports Bottle at hand! 
  • Vomiting: Food poisoning induced vomiting can cause you to lose fluids quickly.
  • Diarrhoea: If you’re suffering from a tummy bug, we recommend rehydrating with electrolytes for a rapid boost of hydration.
How to prevent yourself from getting a dehydration headache?

It seems almost trite to say this but the best thing you can do is drink enough water (2 litres for adults and ½ litre for children <6 years old). Your body needs a certain amount of fluid to function and dehydration is one of the most common reasons behind headaches. Besides this, here are some other things that might prevent yourself from getting a dehydration headache: 

  • Avoid caffeine, alcohol, and sugary drinks. Beverages containing caffeine like coffee, tea and soda cause dehydration as they increase urine production when you have them in large amounts. Alcohol and sugary drinks also cause diuresis (increased urination) when drunk in large quantities and don’t offer any nutritional value.

  • Avoid strenuous exercise in hot weather as this increases your risk for heat exhaustion or stroke (especially if you’re older than 65 years old). When you participate in strenuous activity, you typically release body heat through perspiration. This however, cannot take place if it’s too hot outside as the sweat evaporates much quicker. Our recommendation? Keep physical activity to when it’s cooler outdoors e.g. night time. Having an evening jog or a night-time swim is still a good workout with less physical exertion on your body. 
How long does a dehydrated headache last?

A dehydrated headache usually goes away within an hour or two after you drink enough (approximately 16 – 32 fl oz of water). If you’ve been dehydrated for a long time or have severe dehydration, you would need more time and rest until the pain disappears.

Where is a dehydration headache normally located?

There isn’t really one fixed spot to feel a headache. The pain may occur all over your head or in one spot e.g. just the back, front or side. The pain also varies from a dull to a sharp ache, and some people report feeling a throbbing headache while others feel a constant pain. These are some of the headaches you might get from dehydration:

  • Migraine – A migraine occurs when the brain's nerve cells become inflamed and swollen. This is usually triggered by visual or sensory symptoms that occur before the migraine attack begins and comes with some side effects e.g. nausea/vomiting.
  • Tension-type headache (TTH) – This is when muscles around your eyes and forehead tighten up due to stress/tension. This causes pain on either one side of the head or both sides at different times of day. Unlike migraines though, it doesn’t cause nausea or vomiting. 
  • Cluster headaches – A constant throbbing around one eye almost all day long. This usually goes away after several hours of sleep but it may come back later in the night/early morning. This typically affects about 1% of adults worldwide. 

Our advice? Don’t let it get that far and keep chugging from your bottle!


To sum it up, suffering a headache from dehydration is very common. But the good news is you can easily prevent it by staying hydrated and drinking enough fluids. If you’re already feeling a little unwell, try to avoid hot weather and stress, as well as caffeinated and alcoholic drinks as they will worsen your symptoms.