An Overview of Dehydration

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Water is vital to human survival. When the body loses more water than it takes in, dehydration may occur. Obvious symptoms include thirst and dry mouth or skin, but others like headache, increased heart rate, and confusion can be signs of dehydration as well. At its worst, this condition can be fatal if not addressed and treated promptly.

An athlete drinking water on a sunny day
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Since water is lost through various bodily processes like sweating or urinating, dehydration is more likely to occur with increased physical activity, in warmer temperatures, or when someone is sick (e.g., vomiting).

The good news is that most cases of dehydration can be treated by simply drinking fluids. Sometimes though, with more severe dehydration, fluids will need to be given intravenously or through the vein.


Dehydration is often mild and usually does not cause any symptoms. As it progresses, these symptoms and signs may occur:

  • Feeling thirsty
  • Dry mouth and nose
  • Cracked lips
  • Fatigue and muscle weakness or pain
  • Wrinkled skin
  • Headache
  • Dizziness or lightheadedness
  • Weakness or unusual fatigue
  • Urinating less or having dark urine (may have a strong odor)
  • Increased heart rate and breathing
  • Confusion

Untreated and in extreme cases, dehydration can lead to to kidney failure, seizures, heat exhaustion, stroke, and death.

Children (because their bodies are smaller and they may not be able to communicate that they need something to drink) and the elderly are more prone to dehydration than others, and it's important to be aware of some notable symptoms they may present.

Additional symptoms of dehydration in infants and children may include:

  • No tears when crying
  • No wet diapers for four hours or more
  • Sunken abdomen, eyes, cheeks, or fontanel (the gap between the bones of an infant's skull)
  • High fever
  • Listlessness or irritability

One particular symptom of dehydration that may be pronounced in the elderly is poor skin elasticity. When the skin is pinched, it holds its form rather than returning to its normal shape.


If more water leaves the body than enters it, dehydration may occur. This might, for example, occur with vigorous exercising or when someone has diarrhea.

Excessive urination can also lead to dehydration very quickly. Some of the most common triggers of excessive urination are taking diuretic medications ("water pills"), drinking alcohol, and having certain health conditions, such as high blood sugar (hyperglycemia, a condition seen in untreated diabetes).

Dehydration is also more likely to occur in warmer climates, at higher altitudes, and when someone has a fever.


There is no single test to access for dehydration, although many tools can be helpful, such as accessing vitals (e.g., blood pressure and heart rate) and examining various urine and blood tests. 

Doctors will also perform a physical examination if they are worried about dehydration. There are many signs that point to the diagnosis, such as dry mouth and skin.


If you suspect you are dehydrated, it is important to rehydrate. In addition to water, oral rehydration solutions (e.g., Pedialyte) are good options for mild to moderate dehydration because they provide electrolytes and carbohydrates, which help your body absorb water better.

To avoid nausea and to get the best results, all fluids should be sipped slowly. Drinking too quickly could lead to discomfort or vomiting. In addition, be sure to stay in a cool environment and rest to allow your body to rehydrate without sweating.

If your dehydration is severe, you cannot keep fluids down, or if your symptoms don't subside with fluid intake, go to a hospital so you can be placed under the care of a doctor. In these instances, you will likely receive fluids through the vein (called intravenous fluids) to rehydrate quickly.

With children, be sure to call their doctor if they are experiencing vomiting that lasts for more than one day or diarrhea that lasts more than a few days.

Other reasons to call the pediatrician:

  • Your child cannot keep any fluids down or has not been drinking for many hours.
  • Your older child has not urinated in the last six to eight hours, or your baby or toddler hasn't had a wet diaper in four to six hours.
  • There is blood in your child's vomit or stool.


It is difficult to make precise recommendations as to exactly how much daily water intake any one particular individual needs to avoid dehydration. There are so many factors at play, such as activity level and climate.

The Institute of Medicine (IOM), while not making a recommendation specifically about water intake, recommends that adult men drink approximately 125 ounces (more than 15 cups) of fluids a day; adult women, approximately 90 ounces (over 11 cups). While this may seem a lot, keep in mind, this is total water intake, so it includes fluid from foods as well as beverages.

Of course, if you are engaging in physical activity or have a health condition that requires fluid control, your ideal amount will be different.

Besides drinking fluids, here are some additional tips for preventing dehydration:

  • Seek out shade and avoid prolonged periods of time in the sun.
  • Avoid alcohol and caffeine when possible, but especially when exercising or flying.
  • Be sure to drink fluids several hours prior to exercise.
  • Consume more fruits and vegetables, like cantaloupe and watermelon, to increase your water intake. Of course, this should not be a supplement for drinking pure water.

A Word From Verywell

Dehydration is a serious yet preventable condition. Keep yourself and your children well-hydrated, and remain extra diligent if you (or they) are playing sports, are in the heat, or are sick. If symptoms are severe, do not hesitate to go to the emergency room.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.