Dehydration in Adults Overview
Dehydration is a condition that can occur when the loss of body fluids, mostly water, exceeds the amount that is taken in. With dehydration, more water is moving out of individual cells and then out of the body than the amount of water that is taken in through drinking. Medically, dehydration usually means a person has lost enough fluid so that the body begins to lose its ability to function normally
and then begins to produce symptoms related to the fluid loss. Although infants
and children are at highest risk for dehydration, many adults and especially the
elderly have significant risk factors.
People (and animals) lose water every day in the form of water vapor in the breath we exhale, and as water in our sweat, urine, and stool. Along with the water, small amounts of salts or
electrolytes are also lost.
Our bodies are constantly readjusting the balance between water (and salts or electrolytes) losses with fluid intake. When we lose too much water, our bodies may become out of balance or dehydrated. Most
doctors divide dehydration into three stages: 1) mild, 2) moderate and 3) severe. Mild and often even moderate dehydration can be reversed or put back in balance by oral intake of fluids that contain electrolytes (or salts) that are lost during activity. If unrecognized and untreated, some instances of moderate and severe dehydration can lead to death. This article is designed to discuss dehydration in adults.
Causes of Dehydration in Adults
Many conditions may cause rapid and continued fluid losses and lead to
heat exposure, too much exercise,
or work-related activity
- Vomiting, diarrhea, and increased urination due to infection
- Diseases such as diabetes
- The inability to seek appropriate water and food (an infant or disabled person, for example)
- An impaired ability to drink (someone in a coma or on a respirator, or a sick infant who cannot suck on a bottle are common examples)
- No access to safe drinking water
- Significant injuries to skin, such as burns or mouth sores, severe skin diseases, or infections (water is lost through the damaged skin)
In addition to drinking water, the body also needs replacement of electrolytes
(for example, potassium and sodium) lost with the above mentioned conditions, so drinking water without electrolyte replacement may not complete the balance of water and electrolytes the body has lost. Some symptoms (see below) may remain if this balance is not restored.
Dehydration in Children
Symptoms and Signs of Dehydration in Children
Be concerned if your child has an excessive loss of fluid by vomiting or diarrhea, or if the child refuses to eat or drink.
Signs of dehydration include:
- Sunken eyes
- Decreased frequency of urination or dry diapers
- Sunken soft spot on the front of the head in babies (called the fontanel)
- No tears when the child cries
- Dry or sticky mucous membranes (the lining of the mouth or tongue)
- Lethargy (less than normal activity)
- Irritability (more crying, fussiness with inconsolability)
Symptoms and Signs of Dehydration in Adults
The signs and symptoms of dehydration in adults range from minor to severe.
Mild to moderate dehydration may include the following:
The above symptoms may quickly worsen and indicate severe dehydration with signs and symptoms are developing; severe dehydration may include the following:
- Severely decreased urine output or no urine output. The urine, if any, produced is concentrated and a deep yellow or amber color.
- Dizziness or lightheadedness that does not allow the person to stand or walk normally.
- Blood pressure drops when the person tries to stand after lying down (low blood pressure or orthostatic hypotension)
- Rapid heart rate
- Poor skin elasticity (skin slowly sinks back to its normal position when pinched)
- Lethargy, confusion, or coma
When to Seek Medical Care
Call a primary care doctor if the affected individual with potentially mild
to moderate dehydration experiences any of the following:
- Increased or constant vomiting for more than a day
- Fever over 101 F
(38.3 C), but less than 103 F (39.4)
- Diarrhea for more than 2 days
- Weight loss
- Decreased urine production
Take the person to the hospital's emergency department if these situations occur:
Dehydration in Adults Diagnosis
The doctor may perform a variety of simple tests at the time of examination or send blood or urine samples to the laboratory. Through tests and examination, the doctor will try to identify the underlying cause or causes that led to the dehydration.
- Fever, increased heart rate, decreased blood pressure, and faster breathing are signs of potential dehydration and other illnesses.
- Taking the pulse and blood pressure while the person is lying down and then after standing up for 1 minute can help determine the degree of dehydration. Normally, when
a person has been lying down and then stands up, there is a small drop in blood pressure for a few seconds. The heart rate speeds up, and blood pressure
returns to normal. However, when there is not enough fluid in the blood because of dehydration and the heart rate speeds up,
but not enough blood is supplied to the brain. The brain senses this condition. The heart beats faster, and if
the person is dehydrated, they often feel dizzy and faint after standing up.
- The color and clarity of urine, the urine specific gravity (the mass of urine
when compared with that of equal amounts of distilled water), and the presence of ketones (carbon compounds
- a sign the body is dehydrated) in the urine may all help to indicate the degree of dehydration.
- Increased glucose in the urine may lead to a diagnosis of diabetes or indicate loss of diabetic control and a cause for the dehydration.
- Excessive protein may signal kidney problems.
- Signs of infections or other diseases, such as
liver disease, may be found.
- The amount of salts or electrolytes (sodium, potassium, bicarbonate) and
glucose as well as indicators of kidney function (BUN and creatinine) may be important to evaluate the degree of dehydration and possible causes.
- A complete blood count (CBC) may be ordered if the doctor thinks an underlying infection is causing the dehydration. Other blood tests, such as
liver function tests, may be indicated to find causes of the symptoms.
Dehydration in Adults Treatment
Treatment for dehydration in adults include home remedies like sipping on water; drinking sports drinks that replace lost nutrients; cooling the body; and removing any excess clothing from the person. Medical treatment for dehydration in adults includes hospitalization and replacement of fluids lost.
Dehydration in Adults Home Remedies
Try to get people who are dehydrated (even those who have been vomiting) to take in fluids in the following ways:
- Sip small amounts of water.
- Drink carbohydrate/electrolyte-containing drinks. Good choices are sports drinks such as Gatorade or prepared replacement solutions (Pedialyte is one example).
- Suck on popsicles made from juices and sports drinks.
- Suck on ice chips.
- Sip through a straw (works well for someone who has had jaw surgery or mouth sores).
Try to cool the person, if there has been heat exposure or if the person has an elevated temperature in the following ways:
- Remove any excess clothing and loosen other clothing
- Air-conditioned areas are best for helping return the affected individual's body temperature to normal and break the heat exposure cycle.
- If air-conditioning is not available, increase cooling by evaporation by placing the person near fans or in the shade, if outside. Place a wet towel around the person.
- If available, use a spray bottle or misters to spray tepid (luke-warm) water on exposed skin surfaces to help with cooling by evaporation.
- Avoid exposing skin to excessive cold, such as ice packs or ice water. This
can cause the blood vessels in the skin to constrict and will decrease, rather
than increase heat loss. Exposure to excessive cold can also cause shivering,
which will increase body temperature, this may cause the dehydration symptoms to
Dehydration in Adults Medical Treatment
Treatment in the Emergency Department centers first on restoring fluid (blood) volume and
electrolytes, and treating any life-threatening symptoms while also trying to
determine the underlying cause(s) of the dehydration.
If the affected individual's core body temperature is greater than 104 F (40 C), doctors will cool the entire body. They may promote cooling by evaporation with mists and fans or cooling blankets and baths.
in moderate to severe dehydration
- If there is no nausea and vomiting, fluid replacement may begin orally
for some patients with moderate dehydration. Patients are asked to drink electrolyte/carbohydrate-containing fluids along with water.
- However, if there are signs of moderate to severe dehydration (elevated resting heart rate,
low blood pressure), fluids are generally given through an IV.
- If the patient's condition improves enough (most symptoms stop) in the Emergency Department,
the patient may be sent home, preferably in the care of friends or family.
This is not an unusual result for many patients that arrive at an Emergency
Department with moderate dehydration symptoms.
- If the patient remains dehydrated, confused, feverish, has persistently abnormal vital signs, or signs of infection,
they will likely be admitted to the hospital for additional treatment.
Acetaminophen (for example, Tylenol) or ibuprofen (for example, Advil) may be used. This can be given by mouth if
the affected person is not vomiting or as a rectal suppository if they cannot take anything by mouth.
Dehydration in Adults Medications
If fever is a cause of dehydration, the use of acetaminophen (for example, Tylenol) or ibuprofen (for example, Advil) may be used. This can be given by mouth if the patient is not vomiting or as a rectal suppository if
the patient cannot take anything by mouth. Intravenous (IV) fluids and IV medication, including some that include electrolytes or medications that help normalize electrolyte levels are often used. Other IV medications may need to be used
to treat underlying causes of dehydration (for example, IV antibiotics for dehydration caused by infection).
Dehydration in Adults Follow-up
- Call or return to your doctor or the hospital as instructed.
- Take prescribed medications as directed.
- Continue to keep the affected individual well hydrated with plenty of sports drinks
- Watch for signs of dehydration in yourself and others.
Dehydration in Adults Prevention
Taking in an adequate amount of fluid and food (they both often contain
adequate electrolytes in a normal diet) is the way most people avoid
dehydration. The USDA recommends the following:
"Because normal hydration can be maintained over a wide range of water
intakes, the Adequate Intake (AI) for total water was set based on the median
total water intake from U.S. survey data (IOM, 2004). The AI for total water
intake for young men and women (age 19 to 30 years) is 3.7 L and 2.7 L per day,
respectively. In NHANES III (study), fluids (drinking water and beverages)
provided 3.0 L (101 fluid ounces; about 13 cups) and 2.2 L (74 fluid ounces or
about 9 cups)
per day for men and women age 19 to 30, representing approximately 81 percent of
total water intake. Water contained in food provided about 19 percent of total
The above are estimates; other research bases the amount of fluid intake on
weight and provides tables to estimate an individual's fluid intake. Dehydration is often preventable even under more stressful
conditions such as participation in sports or work on hot days.
Anticipation of the need for increased fluid intake is a key to prevent
- Plan ahead and take extra sports drinks that contain electrolytes and water
bottles to all outdoor events and work areas where increased sweating, activity,
and heat stress will likely increase
a person's fluid loss. Encourage athletes and
outdoor workers to replace fluids at a rate that equals the loss.
- Avoid exercise and exposure during high heat index (high air temperature
with high humidity) days. Listen to weather forecasts for high heat stress days,
and plan events that must occur outside during times when temperatures are
cooler, usually in the early AM and after sunset..
- Ensure that older people and infants and children have adequate drinking
water and fluids containing electrolytes available, and assist them as necessary.
Make sure that any incapacitated or impaired person is encouraged to drink and
is provided with adequate fluids.
- Avoid alcohol consumption, especially when it is very hot, because alcohol
increases water loss and impairs a person's ability to sense early signs
associated with dehydration.
- People should wear light-colored and loose-fitting clothing if they must be
outdoors when it is hot outside. Carry a personal fan or mister to cool the body
so less fluid is lost through sweating.
- Limit the time a person is exposed to hot temperatures. Find
air-conditioned or shady areas and allow the body to cool between exposures.
Taking someone into a cooled area for even a couple of hours each day will help
prevent the cumulative effects of high heat exposure.
Clemson University has developed recommendations for fluid intake when a
person needs to endure outside activity in hot weather:
Drink the following amounts of fluids when exercising rigorously or in very
- Two cups during the two hours before exercising; 1 to 2 cups within 15
minutes of the activity
- One half to 1 cup every 15 to 20 minutes during exercise (One medium
mouthful of fluid equals about 1 ounce, and 8 ounces equals 1 cup.)
- Drink 3 cups for each pound of body weight lost.
Dehydration can be prevented by making the decision to take actions to stay
Dehydration in Adults Prognosis
When dehydration is treated and the underlying cause identified, most people will recover normally. Dehydration caused by heat exposure, too much exercise, or decreased water intake is generally easy to manage, and
the outcome is
usually excellent. However, the prognosis worsens as the severity of dehydration
increases and also depends on how well the underlying cause responds to
Reviewed on 8/31/2017
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine
Hunter, Janis. "Fluid Needs." Clemson University. 2011.
"Dehydration." Medscape. Updated Dec. 31, 2015.
"Dietary Guidelines for Americans." U.S. Department of Agriculture. Dec. 2010.