dehydration

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Definition

Dehydration is the loss of water and salts essential for normal body function.

Description

Dehydration occurs when the body loses more fluid than it takes in. This condition can result from illness; a hot, dry climate; prolonged exposure to sun or high temperatures; not drinking enough water; and overuse of diuretics or other medications that increase urination. Dehydration can upset the delicate fluid-salt balance needed to maintain healthy cells and tissues.

Water accounts for about 60% of a man's body weight. It represents about 50% of a woman's weight. Young and middle-aged adults who drink when they're thirsty do not generally have to do anything more to maintain their body's fluid balance. Children need more water because they expend more energy, but most children who drink when they are thirsty get as much water as their systems require.

Adults over the age of 60 who drink only when they are thirsty probably get only about 90% of the fluid they need. Developing a habit of drinking only in response to the body's thirst signals raises an older person's risk of becoming dehydrated. Seniors who have relocated to areas where the weather is warmer or dryer than the climate they are accustomed to are even likelier to become dehydrated unless they make it a practice to drink even when they are not thirsty.

Dehydration in children usually results from losing large amounts of fluid and not drinking enough water to replace the loss. This condition generally occurs in children who have stomach flu characterized by vomiting and diarrhea, or who can not or will not take enough fluids to compensate for excessive losses associated with fever and sweating of acute illness. An infant can become dehydrated only hours after becoming ill. Dehydration is a major cause of infant illness and death throughout the world.

Mild dehydration is the loss of no more than 5% of the body's fluid. Loss of 5–10% is considered moderate dehydration. Severe dehydration (loss of 10–15% of body fluids) is a life-threatening condition that requires immediate medical care.

When the body's fluid supply is severely depleted, hypovolemic shock is likely to occur. This condition, which is also called physical collapse, is characterized by pale, cool, clammy skin; rapid heartbeat; and shallow breathing.

Blood pressure sometimes drops so low it can not be measured, and skin at the knees and elbows may become blotchy. Anxiety, restlessness, and thirst increase. After the patient's temperature reaches 107°F (41.7°C) damage to the brain and other vital organs occurs quickly.

— Maureen Haggerty

1. The process of removing water from a substance or compound.
2. Excessive loss of water from the body or from an organ or body part, as from illness or fluid deprivation.

1. Removal of water from a substance. 2. A chemical reaction in which a compound loses hydrogen and oxygen in the ratio 2:1. For instance, ethanol passed over hot pumice undergoes dehydration to ethene:

Drying, normally used for factory-dried, as distinct from wind-dried, materials.

Dehydration (loss of fluids from the body) is a hazard in many sports and can be a serious medical problem. It is also a problem associated with some weight loss techniques, such as steam baths, plastic sweat suits, and diuretic pills (water tablets). Dehydration can result in overheating, a potentially dangerous lowering of blood pressure, and a reduction in the rate at which blood is pumped out of the heart. These effects can lead to illness, heat stroke, and even death. Dehydration can occur during exercise when the amount of fluid lost through sweating is greater than fluid replacement through drinking. It can cause poor performances even in temperate climates. A 2 per cent loss of body weight due to water loss, can lead to a 20 per cent drop in the working capacity of muscles. Dehydration reduces both the speed and strength of muscular contractions. To minimize the risk, water should be freely available during exercise and competitive sports. See also heat stroke and water replacement.

1. the removal of water (for example, from the body or tissue). n 2. a decrease in serum fluid coupled with the loss of interstitial fluid from the body. Dehydration is associated with disturbances in fluid and electrolyte balance.

Definition

Dehydration is the loss of water and salts that are essential for normal body function.

Description

Dehydration occurs when the body loses more fluid than it takes in. Dehydration can upset the delicate fluid-salt balance needed to maintain healthy cells and tissues. The human body is generally over 60 percent water. The body works to maintain water balance through mechanisms such as the thirst sensation. When the body requires more water, the brain stimulates nerve centers to encourage a person to drink in order to replenish the water stores. Water intake can vary widely on a daily basis, influenced by such factors as access to water, thirst, habit, and cultural factors.

The kidneys are responsible for maintaining water balance through the elimination of waste products and excess water. Water is primarily absorbed through the gastrointestinal tract and excreted by the kidneys as urine. The variation in water volume ingested is dependent on the ability of kidneys to dilute and concentrate the urine as needed.

Children need more water than adults because they expend more energy, and most children who drink when they are thirsty get as much water as their systems require. Dehydration in children usually results from losing large amounts of fluid and not drinking enough water to replace the loss. This condition generally occurs in children who have a stomach flu characterized by vomiting and diarrhea or who cannot or will not take enough fluids to compensate for excessive losses associated with fever and sweating of acute illness. Dehydration can result from illness; a hot, dry climate; prolonged exposure to sun or high temperatures; not drinking enough water; and overuse of diuretics or other medications that increase urination.

Types of Dehydration

Dehydration is classified as mild, moderate, or severe based on how much of the body fluid is lost, estimated by loss in bodyweight. Mild dehydration is the loss of no more than 5 to 6 percent loss of body weight. Loss of 7 to 10 percent is considered moderate dehydration. Severe dehydration (loss of over 10 percent of body weight) is a life-threatening condition that requires immediate medical care.

Complications of Dehydration

When the body's fluid supply is severely depleted, hypovolemic shock is likely to occur. This condition, which is also called physical collapse, is characterized by pale, cool, clammy skin; rapid heartbeat; and shallow breathing.

Blood pressure sometimes drops so low it cannot be measured, and skin at the knees and elbows may become blotchy. Anxiety, restlessness, and thirst increase. After a child's temperature reaches 107°F (41.7°C) damage to the brain and other vital organs occurs quickly.

Demographics

Dehydration is a major cause of infant illness and death throughout the world. Dehydration is often a result of gastrointestinal disease and diarrhea in children. Among children in the United States, short-term diarrhea results in approximately 200,000 hospitalizations and 300 deaths per year. In developing countries, dehydration from illness is a common cause of death in children under five years of age, accounting for about 2 million deaths per year.

Causes and Symptoms

Dehydration is a deficit of body water that results when the output of water exceeds intake. Dehydration stimulates a child's thirst mechanism. Causes of dehydration may include the following:

• decreased water or fluid intake
• diarrhea
• vomiting
• excessive heat
• excessive sweating
• fever
• excessive urination (polyuria)
• diuretics or other medication that increase fluid loss
• caffeine or alcohol consumption

Sweating and the output of urine both decrease during dehydration. If water intake continues to fall short of water loss, dehydration worsens and a child may become critically ill.

Reduced fluid intake may be a result of the following:

• appetite loss associated with acute illness
• nausea
• bacterial or viral infection or inflammation of the pharynx (pharyngitis)
• inflammation of the mouth caused by illness, infection, irritation, canker sores, or vitamin deficiency

Other conditions that can lead to dehydration include the following:

• disease of the adrenal glands, which regulate the body's water and salt balance and the function of many organ systems
• diabetes mellitus
• eating disorders
• kidney disease
• chronic lung disease

With mild dehydration, increased thirst and restlessness are usually the only apparent symptoms. In moderately dehydrated children, eyes are somewhat sunken, and the mouth and tongue are dry. Thirst is increased: an older child asks for water, and a younger child drinks eagerly when offered a cup or spoon of water. The skin is less elastic than it should be and is slow to return to its normal position after being pinched. The radial pulse (wrist area) is detectable, but rapid. The soft spot on a baby's head (fontanelle) is somewhat sunken. Two of the following symptoms usually indicate some degree of dehydration: drinks eagerly, thirsty, restless, irritable, sunken eyes, or skin pinch goes back slowly.

Children with severe dehydration are usually lethargic, in a stupor, or even in a coma. Symptoms are even more apparent (deeply sunken eyes without tears, very dry mouth and tongue, rapid and deep breathing). A skin pinch retracts very slowly (over two seconds). Children who are awake are very thirsty, although a child may drink poorly if in a stupor. A child may not have urinated for six hours or longer. When in hypovolemic shock, systolic blood pressure taken in the arm is low or not detectable, the arms and legs are cool, and the nail beds may have a bluish or purplish discoloration. Two of the following symptoms indicate severe dehydration: lethargic or unconscious, very slow skin pinch, sunken eyes, and not able to drink or drinking poorly.

Dehydration can cause confusion, constipation, discomfort, drowsiness, and fever. The skin turns pale and cold, the mucous membranes lining the mouth and nose lose their natural moisture. The pulse sometimes races and breathing becomes rapid. Significant fluid loss can cause serious neurological problems or death.

When to Call the Doctor

A doctor should be notified whenever an infant or child exhibits signs of dehydration or a parent is concerned that a stomach virus or other acute illness may lead to dehydration.

A doctor should also be notified if any of the following is the case:

• Symptoms of dehydration worsen.
• A breast-fed or bottle-fed infant is unable to feed or feeds poorly.
• An infant or child urinates very sparingly or does not urinate at all during a eight-hour period.
• An infant younger than two months of age has diarrhea or is vomiting.
• Dizziness, listlessness, or excessive thirst occurs.
• The child's heart is beating fast.
• The child has dry eyes, sunken eyes, a dry mouth, or is not producing tears.
• There is blood in the stool or vomit.

An infant can become dehydrated within hours after the onset of illness. In general, the smaller the child, the lower the threshold should be for healthcare intervention if dehydration is suspected.

Diagnosis

A child's symptoms and medical history alone usually suggest dehydration. Physical symptoms are usually all that is necessary for diagnosing dehydration, although laboratory tests may be ordered by the physician. Physical examination may reveal shock, rapid heart rate, and/or low blood pressure. Laboratory tests, including blood tests (to check electrolyte levels) and urine tests (e.g. urine specific gravity and creatinine), may be used to evaluate the severity of the problem.

Treatment

Increased fluid intake and replacement of lost electrolytes are extremely important for restoring fluid balances in infants and children who are dehydrated. Treatment is given based on severity of dehydration. Treatment should include two phases: a rehydration phase and a maintenance phase. In the rehydration phase, fluid losses are replaced quickly, within three to four hours until normal hydration is achieved. In the maintenance phase, calories and fluids are given. Rapid refeeding should follow rapid rehydration with the goal of returning the child to an unrestricted, age-appropriate diet including solids. Withholding foods to rest the gut is not recommended. Breastfeeding should be continued at all times through both stages of treatment. Full-strength formula is usually tolerated. Changing formula or diluting to half strength are common practices but are usually unnecessary and may even prolong symptoms and delay nutritional recovery.

To replace calories quickly during acute illness, food should be given as soon as the child will tolerate it. During both rehydration and maintenance phases, fluid losses from vomiting and diarrhea should be replaced continuously. Restricting lactose (milk and milk products) is usually not necessary but may be helpful in a child with a severe intestinal disease or diarrhea in a malnourished child.

Children with minimal dehydration weighing less than 10 kilograms (22 pounds) should be given 60 to 120 mL (2–4 ounces) of an oral rehydration solution (ORS) for each episode of vomiting or diarrheal stool. Those weighing more than 10 kg (22 lbs) should be given 120 to 240 mL (4–8 ounces). Food should not be restricted. Children with mild to moderate dehydration should be given 50 to 100 mL (roughly 2–3.5 ounces) of an ORS per kilogram body weight during two to four hours to replace fluid losses. Additional ORS should be administered to replace ongoing losses from vomiting and diarrhea. In a sick child, a teaspoon, syringe, or medicine dropper can be used to offer a small amount at first with amounts increasing as tolerated. If the child appears to want more, more can be given. Severe dehydration is a medical emergency requiring intravenous fluids immediately.

For moderate or severe dehydration, a child should be treated in a medical facility. Moderate dehydration can be treated orally, but severe dehydration requires the child to take fluids intravenously (IV). When treating dehydration, the underlying cause must also be addressed. For example, if dehydration is caused by vomiting, medications may be prescribed to resolve these symptoms. However, anti-diarrheal medications are not recommended in children. A child who is dehydrated due to diabetes, kidney disease, or adrenal gland disorders must receive treatment for these conditions as well as for the resulting dehydration.

For older children who are mildly dehydrated, just drinking plain water may be all the treatment that is needed. For infants and younger children, especially when ill, drinking a commercial ORS should be encouraged. Parents should follow label instructions when giving children Pedialyte or other commercial products recommended for relieving dehydration. Sports drinks are not recommended as they contain a lot of sugar and may worsen diarrhea.

In order to accurately calculate fluid loss, it is important to chart weight changes every day and keep a record of how many times a child vomits or has diarrhea. Parents should note how many times a baby's diaper must be changed.

Alternative Treatment

Gelatin water may be substituted for electrolyte-replacement solutions if an ORS is unavailable. It is made by diluting a 3-oz package in a quart of water or by adding one-fourth teaspoon of salt and a tablespoon of sugar to a pint of water. Receiving the right amount of electrolytes is very important, and thus homemade remedies such as gelatin (or adding salt or sugar to water) are not recommended because of the potential for quantity errors when mixing. However, these may be useful if ORS cannot be obtained in an emergency. Parents should keep a can of ORS on hand for emergencies.

Formulas containing soy fiber have been reported to reduce liquid stools.

Prognosis

Mild dehydration rarely results in complications. If the cause is eliminated and lost fluid is replaced, mild dehydration can usually be cured quickly.

Vomiting and diarrhea that continue for several days without adequate fluid replacement can be fatal. However, dehydration that is rapidly recognized and treated has a good outcome.

Prevention

Ensuring that children always drink adequate fluids during an illness helps to prevent dehydration. Parents can prevent dehydration in infants and children who are vomiting or who have diarrhea by increasing fluids to compensate for losses. Infants and children with diarrhea and vomiting should be given ORS such as Pedialyte immediately to help prevent dehydration.

Children who are not ill can maintain proper fluid balance by drinking water or fluids even before they are thirsty. Children should drink fluids before going outside to exercise or play (especially on a hot day). Dehydration can usually be prevented by drinking enough fluid for urine to remain the color of pale straw. Water in foods, especially fruits and vegetables, is a great source of fluid. Fruits and vegetables can contain up to 95 percent water, so a well-balanced diet is a good way to stay hydrated.

Parents should know whether any medication their child is taking can cause dehydration and should get prompt medical care to correct any underlying condition that increases the risk of dehydration.

Other methods of preventing dehydration and ensuring adequate fluid intake are as follows:

• eating more soup at mealtime
• drinking plenty of water and juice at mealtime and between meals
• keeping a glass of water nearby

Children should not be given coffee or tea, because they increase body temperature and water loss. Avoiding caffeinated soft drinks may also reduce the risk of dehydration. These beverages are all diuretics (substances that increase fluid loss).

Resources

Books

Batmanghelidj, F. Water: For Health, For Healing, For Life: You're Not Sick, You're Thirsty! New York: Warner Books, 2003.

Kleinman, Ronald E., and the American Academy of Pediatrics Committee on Nutrition. Pediatric Nutrition Handbook, 5th ed. Elk Grove Village, IL: American Academy of Pediatrics, 2003.

Physicians Committee for Responsible Medicine. Healthy Eating for Life for Children. Hoboken, NJ: Wiley, 2002.

Speakman, Elizabeth, and Norma Jean Weldy. Body Fluids and Electrolytes, 8th ed. London: Mosby Incorporated, 2001.

Willett, Walter C., and P. J. Skerrett. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. New York: Simon & Schuster Source, 2002.

Workman, M. Linda. Introduction to Fluids, Electrolytes and Acid-Base Balance. London: Saunders, 2001.

Periodicals

Steiner, M. J., et al. "Is this child dehydrated?" Journal of the American Medical Association 291, no. 22 (June 2004): 2746–54.

Organizations

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007–1098. Web site: www.aap.org.

American College of Emergency Physicians. 1125 Executive Circle, Irving, TX 75038–2522. Web site: www.acep.org.

Web Sites

Rehydration Project. Available online at www.rehydrate.org (accessed November 16, 2004).

"Why Is Dehydration so Dangerous?" Rehydration Project. Available online at www.rehydrate.org/dehydration/index.html (accessed November 16, 2004).

[Article by: Crystal Heather Kaczkowski, MSc. Maureen Haggerty]

Food

Medicine

For more information on dehydration, visit Britannica.com.

The removal of water vapor from air by the use of absorbing or adsorbing materials.

A depletion of fluids from the body that can hinder thermoregulation and cause an increase in core temperature. A reduction of the body's fluid volume may result in a lowering of blood pressure and cardiac output. Dehydration occurs during exercise if the fluid lost through perspiration and urine exceeds fluid replacement. Mild dehydration may cause a general malaise and insomnia, and it leads to poor performances even in temperate climates. A two% loss of body-weight due to water loss can lead to a 20% drop in the working capacity of muscles. Training may increase tolerance to dehydration. See also heat stroke, water replacement.

The removal of water; in chemistry, the loss of two hydrogen atoms for every oxygen atom (see H).

The state when the body loses more water than it takes in. There is a negative fluid balance, so that the circulating blood volume decreases and tissue fluids are reduced and tissues are dehydrated. The clinical syndrome of dehydration includes loosening and wrinkling of the skin, and a bad skin-tenting reaction, in which a pinched-up fold of skin takes longer than normal to disappear; there is usually evidence of the cause of the dehydration, e.g. vomiting, polyuria. Clinical pathological tests are essential to determine the severity of the dehydration.

• cellular d. — caused by increased osmoconcentration of the extracellular fluid.

This article is about the medical condition. For the removal of water through chemical or physical means, see desiccation. For the chemical reaction, see dehydration reaction. For food preservation by dehydration, see drying (food).

Dehydration
Classification and external resources
ICD-10	E86.
ICD-9	276.5

Dehydration (hypohydration) is defined as excessive loss of body water.^[1] It is literally the removal of water (Ancient Greek: ὕδωρ, hýdōr) from an object. In physiological terms, it entails a relative deficiency of water molecules in relation to other dissolved solutes. Some definitions even require a rise in blood sodium concentration^[2], but in reality a loss of body water usually accompanies a loss of solutes as well.^[2]

Contents 1 Difference from hypovolemia 2 Medical causes of dehydration in humans 3 Symptoms and prognosis 4 Treatment 5 Avoiding dehydration 6 See also 7 References 8 Notes 9 External links

Difference from hypovolemia

Hypovolemia is specifically a decrease in volume of blood plasma.^[3][4]. Furthermore, hypovolemia defines water deficiency only in terms of volume rather than specifically water.

Nevertheless, the conditions usually appear simultaneously.

Medical causes of dehydration in humans

In humans, dehydration can be caused by a wide range of diseases and states that impair water homeostasis in the body. These include:

• External or stress-related causes
  • Prolonged physical activity with sweating without consuming adequate water, especially in a hot and/or humid environment
  • Prolonged exposure to dry air, e.g. in high-flying airplanes (5-12% relative humidity)
  • Blood loss or hypotension due to physical trauma
  • Diarrhea
  • Hyperthermia
  • Shock (hypovolemic)
  • Vomiting
  • Burns
  • Lacrimation
  • Use of Methamphetamine, Amphetamine and other stimulants.
  • Drinking of Alcohol. (In place of water)

• Infectious diseases
  • Cholera
  • Gastroenteritis
  • Shigellosis
  • Yellow fever

• Malnutrition
  • Electrolyte disturbance
    • Hypernatremia (also caused by dehydration)
    • Hyponatremia, especially from restricted salt diets
  • Fasting
  • Recent rapid weight loss may reflect progressive depletion of fluid volume (the loss of 1 L of fluid results in a weight loss of 1 kg or 2.2 lb).^[5]
  • Patient refusal of nutrition and hydration
  • Inability to swallow (obstruction of the esophagus)

• Other causes of obligate water loss
  • Severe hyperglycemia, especially in Diabetes mellitus
    • Glycosuria

Symptoms and prognosis

Symptoms may include headaches similar to what is experienced during a hangover, muscle cramps, a sudden episode of visual snow, decreased blood pressure (hypotension), and dizziness or fainting when standing up due to orthostatic hypotension. Untreated dehydration generally results in delirium, unconsciousness, swelling of the tongue and in extreme cases death.

Dehydration symptoms generally become noticeable after 2% of one's normal water volume has been lost. Initially, one experiences thirst and discomfort, possibly along with loss of appetite and dry skin. This can be followed by constipation. Athletes may suffer a loss of performance of up to 30%^[6], and experience flushing, low endurance, rapid heart rates, elevated body temperatures, and rapid onset of fatigue.

Symptoms of mild dehydration include thirst, decreased urine volume, abnormally dark urine, unexplained tiredness, irritability, lack of tears when crying, headache, dry mouth, dizziness when standing due to orthostatic hypotension, and in some cases can cause insomnia.

In moderate to severe dehydration, there may be no urine output at all. Other symptoms in these states include lethargy or extreme sleepiness, seizures, sunken fontanel (soft spot) in infants, fainting, and sunken eyes.

The symptoms become increasingly severe with greater water loss. One's heart and respiration rates begin to increase to compensate for decreased plasma volume and blood pressure, while body temperature may rise because of decreased sweating. Around 5% to 6% water loss, one may become groggy or sleepy, experience headaches or nausea, and may feel tingling in one's limbs (paresthesia). With 10% to 15% fluid loss, muscles may become spastic, skin may shrivel and wrinkle (decreased skin turgor), vision may dim, urination will be greatly reduced and may become painful, and delirium may begin. Losses greater than 15% are usually fatal. ^[7]

In people over age 50, the body’s thirst sensation diminishes and continues diminishing with age. Many senior citizens suffer symptoms of dehydration. Dehydration along with hyperthermia results in seniors dying during extreme hot weather.

Dehydration is the excessive loss of water from the body. Diseases of the gastrointestinal tract can lead to dehydration in various ways. Often, dehydration becomes the major problem in an otherwise self-limited illness. Fluid loss may even be severe enough to become life-threatening.

Numerous studies have shown that for terminally ill patients who choose to die, deaths by dehydration are generally peaceful, and not associated with suffering, when supplemented with adequate pain medication.^{[8][9][10][11][12][13]}

Treatment

This article contains instructions, advice, or how-to content. The purpose of Wikipedia is to present facts, not to train. Please help improve this article either by rewriting the how-to content or by moving it to Wikiversity or Wikibooks. (April 2009)

Nurses encourage a patient to drink an Oral Rehydration Solution to improve dehydration he acquired from cholera.

The best treatment for minor dehydration is drinking water and stopping fluid loss. Sports drinks and other rehydration fluids are preferable to water; plain water restores only the volume of the blood plasma, inhibiting the thirst mechanism before solute levels can be replenished.^[14] To stop fluid loss from vomiting and diarrhea, avoid solid foods and drink only clear liquids. In some cases, eating of salted foods may have a positive impact on the person. However, eating salted foods should come with more intake of a clear liquid. It is wise to slowly drink liquids when dehydrated. ^[15]

In more severe cases, correction of a dehydrated state is accomplished by the replenishment of necessary water and electrolytes (rehydration, through oral rehydration therapy or intravenous therapy). Even in the case of serious lack of fresh water (e.g., at sea or in a desert), drinking seawater or urine does not help, nor does the consumption of alcohol. It is often thought that the sudden influx of salt into the body from seawater will cause the cells to dehydrate and the kidneys to overload and shut down but it has been calculated that an average adult can drink up to 0.1 liters of seawater per day before the kidneys start to fail^{[citation needed]}

When dehydrated, unnecessary sweating should be avoided, as it wastes water. If there is only dry food, it is better not to eat, as water is necessary for digestion. For severe cases of dehydration where fainting, unconsciousness, or other severely inhibiting symptom is present (the patient is incapable of standing or thinking clearly), emergency attention is required. Fluids containing a proper balance of replacement electrolytes are given orally or intravenously with continuing assessment of electrolyte status; complete resolution is the norm in all but the most extreme cases.

Avoiding dehydration

Dehydration is best avoided by drinking plenty of water. The greater the amount of water lost through perspiration, the more water must be consumed to replace it and avoid dehydration. Since the body cannot tolerate large deficits or excesses in total body water, consumption of water must be roughly concurrent with the loss (in other words, if one is perspiring, one should also be drinking water frequently). Drinking water beyond the needs of the body entails little risk when done in moderation, since the kidneys will efficiently remove any excess water through the urine with a large margin of safety.

A person's body, during an average day in a temperate climate such as the United Kingdom, loses approximately 2.5 litres of water.^{[citation needed]} This can be through the lungs as water vapor, through the skin as sweat, or through the kidneys as urine. Some water (a less significant amount, in the absence of diarrhea) is also lost through the bowels. In warm or humid weather or during heavy exertion, however, the water loss can increase by an order of magnitude or more through perspiration; all of which must be promptly replaced. In extreme cases, the losses may be great enough to exceed the body's ability to absorb water from the gastrointestinal tract; in these cases, it is not possible to drink enough water to stay hydrated, and the only way to avoid dehydration is to reduce perspiration (through rest, a move to a cooler environment, etc.)

A useful rule of thumb for avoiding dehydration in hot or humid environments or during strenuous activity involves monitoring the frequency and character of urination. If one develops a full bladder at least every 3-5 hours and the urine is only lightly colored or colorless, chances are that dehydration is not occurring; if urine is deeply colored, or urination occurs only after many hours or not at all, water intake may not be adequate to maintain proper hydration.

When large amounts of water are being lost through perspiration and concurrently replaced by drinking, maintaining proper electrolyte balance becomes an issue. Drinking fluids that are hypertonic or hypotonic with respect to perspiration may have grave consequences (hyponatremia or hypernatremia, principally) as the total volume of water turnover increases.

If water is being lost through abnormal mechanisms such as vomiting or diarrhea, an imbalance can develop very quickly into a medical emergency.

During sports events such as marathons, water stops and water breaks are provided to avoid dehydration of athletes.

See also

• Hypovolemia, a depletion of blood volume that can be caused by dehydration
• Safe water
• Starvation
• Water intoxication
• Water therapy
• Water deprivation test

References

• Ira R. Byock, M.D., Patient Refusal of Nutrition and Hydration: Walking the Ever-Finer Line. American Journal Hospice & Palliative Care, pp. 8-13. (March/April 1995)

Notes

1. ^ MedicineNet > Definition of Dehydration Retrieved on July 2, 2009
2. ^ ^{a b} TheFreeDictionary.com --> dehydration Citing The American Heritage Science Dictionary 2005. Retrieved on July 2, 2009
3. ^ MedicineNet > Definition of Hypovolemia Retrieved on July 2, 2009
4. ^ TheFreeDictionary.com --> hypovolemia Citing Saunders Comprehensive Veterinary Dictionary, 3 ed. Retrieved on July 2, 2009
5. ^ Dehydration Symptoms - Benefits of Drinking Water - Signs of Fluid Imbalance
6. ^ Bean, Anita (2006). The Complete Guide to Sports Nutrition. A & C Black Publishers Ltd.. pp. 81–83. ISBN 0713675586. 
7. ^ http://faculty.washington.edu/kepeter/118/notes/pdf-set5/118water-bal-06.htm
8. ^ Ganzini L, Goy E, Miller L, Harvath T, Jackson A, Delorit M (2003). "Nurses' experiences with hospice patients who refuse food and fluids to hasten death". N Engl J Med 349 (4): 359–65. doi:10.1056/NEJMsa035086. PMID 12878744. 
9. ^ McAulay D. "Dehydration in the terminally ill patient". Nurs Stand 16 (4): 33–7. PMID 11977821. 
10. ^ Van der Riet P, Brooks D, Ashby M (2006). "Nutrition and hydration at the end of life: pilot study of a palliative care experience". J Law Med 14 (2): 182–98. PMID 17153524. 
11. ^ Miller F, Meier D (1998). "Voluntary death: a comparison of terminal dehydration and physician-assisted suicide". Ann Intern Med 128 (7): 559–62. PMID 9518401. 
12. ^ Printz L (1992). "Terminal dehydration, a compassionate treatment". Arch Intern Med 152 (4): 697–700. doi:10.1001/archinte.152.4.697. PMID 1373053. 
13. ^ Sullivan R (1993). "Accepting death without artificial nutrition or hydration". J Gen Intern Med 8 (4): 220–4. doi:10.1007/BF02599271. PMID 8515334. 
14. ^ "Formulating carbohydrate-electrolyte drinks for optimal efficacy." Murray, R. & Stofan, J. (2001).
15. ^ "Healthwise Handbook," Healthwise, Inc. 1999

External links

Look up dehydration in Wiktionary, the free dictionary.

• Water requirements in adults
• Definition of dehydration by the U.S. National Institutes of Health's MedlinePlus medical encyclopedia
• Rehydration Project at rehydrate.org

v • d • e Water-electrolyte imbalance and acid-base imbalance (E86-E87, 276) Volume status Volume contraction (Dehydration/Hypovolemia)  · Hypervolemia Electrolyte Na+ Hypernatremia · Hyponatremia (Hypoosmolar hyponatremia, Pseudohyponatremia) K+ Hyperkalemia · Hypokalemia Cl− Hyperchloremia · Hypochloremia Acid-base Acidosis Metabolic: High anion gap (Ketoacidosis/Diabetic ketoacidosis, Lactic) · Normal anion gap (Hyperchloremic, Renal tubular) Respiratory Alkalosis Metabolic: Contraction alkalosis Respiratory Both Mixed disorder of acid-base balance

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