Dehydration occurs when more fluid is lost than is taken in. Water, in particular, is a vital part of our health and it is important to replenish our bodies by consuming water and other fluids. As much as 60% of the body, 75% of muscle, 80% of blood, and 85% of our brain is made of water.

Studies have shown that as many as 75% of Americans are chronically dehydrated, and drink less than the recommended 8-10 cups of water each day. Globally, dehydration is a major cause of illness and death in infants, as well as a common cause of hospitalization in the elderly population.

Most cases of dehydration are mild and easily treatable by rehydration and rest. Some severe cases of dehydration can become life-threatening if not treated in a timely manner. Water losses comprising 9-12% of total body weight can be serious, and are often fatal.

What is Dehydration?

When there is more water going out of the body than coming in, the result is volume depletion or dehydration. Water is lost in many ways – through water vapor from exhalation and breathing, or water that is lost through sweat, urine and stool. As much as 10 cups of water per day are lost through these methods, in addition to losing small amounts of salts.

Loosing too much water without replacing it causes our bodies to become out of balance. Severe cases of dehydration may lead to serious complications, including death.

Babies and young children are most at risk of dehydration, due to their small body size, susceptibility to infection, and higher metabolic rate. The elderly are also at higher risk of dehydration, due to impaired kidney function, the inability to control their bladders, difficulty getting up to use the bathroom, or even difficulty holding a glass. Elderly patients are sometimes not aware of their thirst, due to a less sensitive thirst center, compared to the younger population.

There are three stages of dehydration – mild, moderate, and severe. Typically, mild and moderate dehydration can be treated with little to no long-term side effects, often using oral or intravenous rehydration fluids. Severe and some moderate cases of dehydration can lead to complications, such as death, particularly if untreated. Other consequences of severe dehydration include shock, and severe damage to internal organs. Organs including the kidneys, liver, and brain are often damaged due to severe dehydration. Confusion and coma are often signs of brain damage from dehydration.

The recommended amount of water intake each day depends on several factors, including a person’s weight. A table of suggested fluid intake is below, although this may change depending on a person’s physical activity, urine production, or the presence of fever, vomiting, or diarrhea.

Body Weight Daily Fluid Requirements (approximate)
10 pounds 5 ounces
20 pounds 10 ounces
30 pounds 15 ounces
40 pounds 20 ounces
50 pounds 25 ounces
75 pounds 37.5 ounces
100 pounds 50 ounces
150 pounds 75 ounces
200 pounds 100 ounces
250 pounds 125 ounces
300 pounds 150 ounces
350 pounds 175 ounces
400 pounds 200 ounces

What Causes Dehydration?

Dehydration and losing too much fluid may be due to an array of issues or conditions. Some common conditions that lead to dehydration include:

  • Vomiting
  • Diarrhea
  • Nausea
  • Physical exertion, such as intense exercise
  • Decreased water intake
  • Fever
  • Heat exposure
  • Use of diuretics
  • Diabetes
  • Addison’s disease
  • Lack of access to viable, safe drinking water
  • Medical condition that impairs the ability to drink water, such as a coma
  • Skin injuries
  • Burns
  • Mouth Sores
  • Skin infections
  • Increased or excessive sweating
  • Humid climate, often due to excessive sweating
  • Increased or excessive urination

Signs and Symptoms of Dehydration

Thirst is not always a reliable indicator of hydration, particularly in children or the elderly. Urine color can be a useful gauge of hydration levels. Clear or lighter-colored urine signals a well-hydrated body, while dark yellow or amber-colored urine indicates dehydration.

Symptoms of dehydration are often separated into two categories – symptoms of mild to moderate dehydration, and symptoms of severe dehydration.

Signs of mild to moderate dehydration include:

  • Increased thirst
  • Lethargy – sleepiness, tiredness, children may be less active than normal
  • Weakness
  • Dry, sticky mouth
  • Decreased urination
  • Headache
  • Muscle cramps
  • Urine that is darker than normal
  • Reduced sweating, or inability to sweat
  • Reduced skin elasticity
  • Constipation
  • Dry skin
  • Infants with lack of wet diapers for three hours or more
  • Reduced amount of tears if crying

Signs of severe dehydration include:

  • Dizziness
  • Lightheadedness, especially upon standing
  • Fainting
  • Rapid heartbeat
  • Rapid breathing
  • Severe weakness
  • Extremely dark-colored urine – very dark yellow, amber-colored
  • Lack of urine
  • Irritability
  • Confusion
  • Sunken eyes
  • Unconsciousness
  • Delirium
  • Extreme fussiness or sleepiness in children
  • Very dry mouth
  • Very dry skin
  • Skin that lacks elasticity
  • Low blood pressure
  • Low pulse rate
  • Rapid breathing
  • Lack of tears if crying
  • Lack of sweat
  • Seizure
  • Sunken or soft spot on the forehead in infants (sunken fontanelle)

Prevention of Dehydration

The easiest way to prevent dehydration is to remain adequately hydrated throughout the day, taking prudent care to consume fluids following exercise, when in a hot and humid environment, or during an illness.
Planning ahead by taking extra water or sports drinks to sporting activities or outdoor events is a helpful way to prevent dehydration.

Avoiding exercise during high-heat warnings may also prevent or reduce chances of dehydration.

Monitoring children and the elderly, and ensuring they are adequately hydrated throughout the day can minimize their risk of dehydration.

Avoiding or minimizing alcohol intake while in a hot environment can reduce dehydration experienced with alcohol consumption.

Treatment of Dehydration

Often, rest and hydration will help improve dehydration symptoms. Avoiding exercise and strenuous physical activity helps prevent further dehydration. Resting, cooling off the body in an air-conditioned area, and removing excess clothing may also help relieve symptoms of dehydration.

Oral rehydration solutions that contain water and salts to replenish fluids and electrolytes are often helpful in the treatment of dehydration. Children may benefit from an electrolyte drink such as Pedialyte. Liquids such as cool water, sports drinks with electrolytes, fruit juice without pulp, broths (clear broths are recommended,) Jell-O, popsicles, soda without caffeine, and tea with honey are helpful ways to stay hydrated. Sucking on ice cubes is another way to hydrate. Drinking through a straw may be helpful for patients who have just had jaw surgery or who currently have mouth sores. This may help increase oral fluids and prevent further dehydration. Babies who are currently being breastfed should continue to be breastfed, and caregivers should supplement their intake with an oral rehydration solution in a bottle.

Try to avoid fluids that contain caffeine or alcohol, carbonated beverages, as well as soft drinks that are high in sugar or corn syrup. Avoid taking salt tablets, as they may lead to complications and electrolyte imbalances.

If the cause of dehydration is vomiting, diarrhea, or another medical condition, treatments for these underlying causes can aid in the treatment of dehydration.

If the cause of dehydration is an underlying fever, over-the-counter medication such as acetaminophen (Tylenol) or ibuprofen (Advil) may provide some relief.

If a patient has experienced severe fluid loss or is extremely dehydrated, a medical team may administer intravenous (IV) fluids to compensate for the loss.

When Should I Call a Doctor?

Young children, infants and the elderly should be carefully evaluated at even the first sign of suspected dehydration.

To avoid further progression to serious dehydration, seeking medical treatment for symptoms of even mild to moderate dehydration is recommended. Consider speaking with your primary care physician, or requesting a visit to speak with a telemedicine provider. A medical provider can offer rehydration solutions, determine underlying causes that may be inducing dehydration, as well as provide advice to best manage your case of dehydration.

Emergency Warning Signs

Patients who become extremely dehydrated should seek urgent medical attention right away. Symptoms such as confusion, extreme sleepiness, or unconsciousness may indicate brain damage and warrant immediate medical care.

Symptoms of severe dehydration can lead to consequences such as internal organ damage or death, if not treated. Other complications of severe dehydration include kidney failure, coma, shock, heat-related complications and illnesses, and electrolyte abnormalities.

Other symptoms of dehydration that signal the need for a medical evaluation include:

  • Extreme thirst
  • Shriveled skin
  • Dizziness and confusion
  • Lethargy
  • Coma
  • Fainting
  • Irritable and disoriented
  • Fever higher than 101 degrees F
  • Diarrhea for more than 2 days
  • Weight loss
  • Extreme weakness
  • Seizures
  • Difficulty breathing
  • Chest pain
  • Abdominal pain
  • Fainting
  • Lack of urine for 12 hours or more
  • Severe diarrhea
  • Stool that is bloody or black
  • Unable to keep down fluids
  • Uncontrollable vomiting
  • Symptoms of a heatstroke – rapid pulse, rapid breathing
  • Dehydration that worsens or does not appear to improve despite increasing fluids