Can Dehydration Cause Headache?

Dehydration can cause both sudden or chronic headaches.

Causes of a sudden dehydration headache:

  • Occasional pressure-like headache due to not drinking enough water, especially after physical exertion and in a hot weather
  • Migraine, a pulsating, one- or both-sided headache with nausea and sensitivity to light, appearing shortly after a skipped meal or exertion in a hot weather
  • Hangover, an intense, throbbing headache, usually both-sided, appearing several hours after excessive alcohol drinking, aggravated by bending down or moving around, accompanied by thirst, nausea, fatigue, sensitivity to light and diarrhea
  • Headache due to water loss caused by vomiting, diarrhea, heavy menstrual bleeding, burns, heat stroke

Causes of a chronic dehydration headache:

  • Chronic headache due to insufficient water intake. By not drinking enough, you can easily get dehydrated even in winter and when you are not physically active.
  • Water loss caused by excessive intake of caffeine or alcohol
  • Water loss caused by medications, like diuretics, antihistamines or calcium channel blockers 
  • Chronic headache with thirst and excessive urination in untreated diseases, like diabetes mellitus, diabetes insipidus (due to pituitary tumor), kidney or adrenal gland disorder  

Headaches and Other Symptoms of Dehydration

A headache is usually not the only or main symptom of dehydration. Symptoms of mild to moderate dehydration may include:

  • Dry and sticky mouth and lips
  • Thirst (not always!)
  • Fatigue and weakness
  • Dizziness
  • Visual snow when standing up from a sitting position
  • Dry, wrinkled skin that flattens slowly when pinched and released
  • Low amount of dark colored urine
  • Headache
  • Constipation

Additional symptoms in severe dehydration:

  • Irritability or confusion
  • Rapid heart beat
  • Fainting
  • Tingling in limbs
  • Muscle cramps
  • Low blood pressure
  • Little or no urine
  • Seizures
  • Swollen tongue
  • In extreme cases, unconsciousness and death may follow

How To Prevent Dehydration Headaches?

  • Drink enough water. Amount of water you need depends on what you eat, environmental temperature, physical effort, eventual diseases you have or medications you take. A common recommendation is 2 liters (8 cups) of water a day, but if you consume a lot of fruits, vegetables and broths, you might not need so much. On a hot day and if you are physically active, you might need more, though.
  • If you suffer from a chronic headache, try to maintain regular eating schedule
  • If possible, avoid heavy physical work in a hot weather
  • Avoid excessive amounts of alcohol or caffeine

Treatment of Dehydration Headache

Treatment of headache caused by dehydration depends on its exact cause. If you are otherwise healthy, drink several cups of water, one cup every 30 minutes or so. Do not drink coffee, black tea, caffeinated drinks or alcohol.

If you have a sudden, severe headache, you have a heart or kidney disease, or you think your headache is caused by medications, call or visit your doctor before drinking excessive amounts of fluid.

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Article reviewed by Dr. Greg. Last updated on June 11, 2010