Dehydration Diagnosis and Treatment in Adults

By , August 28th 2013. Last reviewed 17th September 2016.

Dehydration Treatment at a Glance

  • Mild and moderate dehydration can be treated with drinking fluids or eating certain fruits or vegetables (see the charts below).
  • Severe dehydration is a life-threatening condition, which may require intravenous fluid infusion.

How do I know how dehydrated am I?

Your physical symptoms can tell you which dehydration stage you are in (Chart 1) 1.

Chart 1. Dehydration Stages

Weight loss 1-3% 3-6% >6%
Urination Slightly
Decreased Little or
no urine
Urine color Clear or
pale yellow
Yellow to brown
Skin recoil after
pinch and release
(skin turgor test)
Instant Delayed
(up to 2 seconds)
(>2 seconds)
Mouth and lips Moist Dry Chapped lips

Chart explanation:

  • Sudden weight loss (hours/few days) is very likely caused by dehydration and not loss of fat (except in prolonged, hard physical work or exercise, such as marathon), so it is considered as a most reliable diagnostic sign of dehydration.
  • Decreased frequency of urination and decreased amount of excreted urine are another reliable signs of dehydration.
  • Other symptoms and signs mentioned in the chart also strongly suggest dehydration, but are less reliable (may be present in well hydrated persons and absent in dehydrated ones).

Skin Turgor Test

Definition. Skin turgor is skin elasticity, which is skin’s ability to return to normal shape after being pinched and released. Skin turgor is a quick test for assessment of moderate and severe dehydration. In mild dehydration, skin turgor may be normal.

Pinch the skin on the back of the hand (preferably in the area between the thumb and index finger) and release it. Normally, the skin should flatten immediately; any delay in skin recoil suggests dehydration (Chart 1).

Skin turgor test cannot be performed in some older people who have poor skin turgor even when well hydrated, and is unreliable in some obese persons who have normal skin turgor even when dehydrated.

First Aid in Dehydration

How to help acutely dehydrated person:

  1. Give some appropriate drink (see the chart below) to a dehydrated person (as much as he or she can drink comfortably, but not more than three liters in one hour), even if he or she does not feel thirsty. Do not give plain water to an infant.
  2. If necessary, move a person to a cool or at least shadowy place.
  3. If a person looks severely dehydrated, cannot drink due to nausea or injury or has impaired consciousness call a doctor. A severely dehydrated person should lie with legs raised.

What should I drink to relieve MILD or MODERATE dehydration?

CHART 2: Appropriate and inappropriate drinks to treat dehydration

Water Any safe water is fine: tap water, bottled water, including mineral and carbonated water, clean streams or lakes
Herbal tea
Decaffeinated coffee
Sport drinks Sport drinks are intended for long lasting (3-4 hours) hard physical work (marathon); usually no need to drink in <2 hours activities.
Fruit juices Sugar (in large amounts) may trigger diarrhea.
Soft drinks (soda, cola) Sugar
Iced tea Sugar
Green or black tea Caffeine in large amounts can cause caffeine intoxication. Caffeine can transitionally stimulate urine excretion, but not significantly and is about as much effective in relieving dehydration as plain water 2,5.
Regular (caffeinated) coffee Caffeine
Energy drinks Sugar, caffeine
Milk Milk in large amounts may trigger diarrhea, especially in lactose intolerant people. Skim milk goes through the stomach faster than whole milk.
Clear soups Salt from large amount of soup may trigger diarrhea.
Beer, cider or other weak alcoholic beverages (up to 4-5 vol% alcohol) Large amount of beer can cause alcohol intoxication. Alcohol can transitionally stimulate urine excretion, but beer is not dehydrating 2,3, so, when no other beverage is available, drinking beer can relieve mild or moderate dehydration.
Apple juice, pear juice, mango juice, and beverages with HFCS  Beverages, which contain high amounts of “net fructose” may trigger diarrhea and thus worsen dehydration, especially in individuals with fructose malabsorption.Amount of net fructose in 1 liter of beverage:

  • Pear juice: 58 g
  • Apple juice: 31 g
  • Cola, sweetened with HFCS: 17 g
Water contaminated with microbes or toxins May trigger diarrhea and thus worsen dehydration.
Strong alcoholic drinks (wine, liquers, spirits) You can get intoxicated by alcohol before getting rehydrated.
Seawater 33 After drinking seawater, the human kidneys, in order to excrete excessive salt, need to excrete more water than you’ve got it with seawater. Explanation: By drinking 1 liter of seawater, which contains about 3.5% of salt, you consume 1,200 milliosmoles (mOsm) of excessive salt, which needs to be excreted by the urine. The kidneys can excrete only about 1,200 mOsm of solutes per liter but they also need to excrete about 600 mOsm per liter of urea and other products of metabolism, so they can excrete only 600 mOsm of salt per liter urine. The remaining 600 mOsm of salt from seawater will need additional 0.5 liter of urine in order to be excreted. In summary: When you drink 1 liter of seawater, you may need to excrete about 1.5 liters of urine to get rid of excessive salt, which results in 0.5 liter of net water loss, which means further dehydration.

Can I eat fruits or vegetables to relieve MILD or MODERATE dehydration?

Most fruits contain more than 80-90% water, so theoretically, you could correct mild or moderate dehydration by eating fruits only. The problem is that you can not eat fruits as fast as you can drink fluids and you may get severely bloated after large amount of fruits. Eating large amounts of fruits high in fructose (Chart 3) can trigger diarrhea.

CHART 3. Amount of water, sugar, fiber and calories in 1 kg (2.2 pounds) fruits and vegetables

  • Water: 860 g
  • Sugars: 110 g
  • Fiber: 20 g
  • Calories: 480
  • Water: 920 g
  • Sugars: 32 g
  • Fiber: 25 g
  • Calories: 250
  • Water: 750 g
  • Sugars: 120 g
  • Fiber: 26 g
  • Calories: 890
  • Water: 880 g
  • Sugars: 47 g
  • Fiber: 28 g
  • Calories: 410
  • Water: 880 g
  • Sugars: 70 g
  • Fiber: 16 g
  • Calories: 420
  • Water: 845 g
  • Protein: 30 g
  • Fiber: 20 g
  • Calories: 500
Honeydew melon
  • Water: 900 g
  • Sugars: 80 g
  • Fiber: 8 g
  • Calories: 360
Leeks (bulb and lower leaf)
  • Water: 830 g
  • Sugars: 40 g
  • Fiber: 18 g
  • Calories: 610
  • Water: 830 g
  • Sugars: 90 g
  • Fiber: 30
  • Calories: 610
  • Water: 920 g
  • Sugars: 14 g
  • Fiber: 5 g
  • Calories: 260
  • Water: 850 g
  • Sugars: 106 g
  • Fiber: 18 g
  • Calories: 530
Tomato (orange)
  • Water: 950 g
  • Sugars: 0 g
  • Fiber: 9 g
  • Calories: 160
  • Water: 870 g
  • Sugars: 94 g
  • Fiber: 24 g
  • Calories: 470
Turnip (flesh)
  • Water: 920 g
  • Sugars: 38 g
  • Fiber: 18 g
  • Calories: 280
  • Water: 890 g
  • Sugars: 84 g
  • Fiber: 15 g
  • Calories: 390
  • Water:
  • Sugars: 98 g
  • Fiber: 14 g
  • Calories: 500
  • Water: 870 g
  • Sugars: 100 g
  • Fiber: 14 g
  • Calories: 460
  • Water: 860 g
  • Sugars: 44 g
  • Fiber: 65 g
  • Calories: 520
  • Water:
  • Sugars: 50 g
  • Fiber: 20 g
  • Calories: 320
  • Water: 920 g
  • Sugars: 62
  • Fiber: 4
  • Calories: 300
  • Water: 730 g
  • Sugars: 7 g
  • Fat: 150 g
  • Protein: 20 g
  • Fiber: 67 g
  • Calories: 1,600 (slow gastric emptying)
 Lettuce You need to eat it a lot to get some water
  • Water: 813 g
  • Sugars: 162 g
  • Fiber: 9 g
  • Calories: 670 g
  • Water: 855 g
  • Sugars: 104 (32 g net fructose)
  • Fiber: 24
  • Calories: 520
Raw potato Eating raw potatoes can  cause fever
  • Water: 820 g
  • Sugars: 148 g (27 g net fructose)
  • Fiber: 18 g
  • Calories: 650
  • Water: 840 g
  • Sugars: 98 g (38 g net fructose)
  • Fiber: 31 g
  • Calories: 580

* Chart 2 reference: 4 ; Most healthy people can absorb about 25-40 grams of “net fructose” (= grams fructose – grams glucose) from one meal, but many people with fructose malabsorption can absorb less than 25 grams of net fructose. 1,000 grams of fruits, such as apples, pears and mangoes contain more than 25 grams of net fructose, which may not be fully absorbed and can therefore trigger diarrhea in individuals with fructose malabsorption and thus worsen dehydration.

How much and for how long should I drink to relieve MILD or MODERATE dehydration?

To properly rehydrate yourself, you may need to drink 1.5 x amount of fluid you have lost: after losing 3 kilograms of body weight, you need to drink about 4.5 liters of water 5,6; the additional 1.5 liter of water is to replace water lost in urine during rehydration. Doctors usually recommend replacing one half of lost fluid in the first 4 hours and the other half in the next 8 hours 34.

Recovery Time

It may take more than 24 hours before you become completely rehydrated, because some of the fluid you drink and that enters your circulation is excreted with the urine before it reaches your body cells 5. In conclusion, you need to drink until you reach your usual body weight and your urine is clear in several successive voidings.

What should I do after waking up dehydrated?

When you go to bed mildly dehydrated you may wake up moderately dehydrated in the morning. During sleeping on a hot night you can lose more than one liter of water by sweating and breathing.

Weigh yourself so you can see how much water have you lost (in case you have lost more than 6% of your usual body weight, visit a doctor). In case, you have lost less than that, you can have your regular breakfast with some appropriate beverage from the Chart 2 above. Drink the amount to quench your thirst, but be prepared to drink more soon after – over the day you should drink as much as needed to restore your usual body weight.

Diet During Dehydration (What to Eat)

During dehydration you can have your usual meals. Avoid foods that can cause constipation (low-fiber foods such as chocolate, French fries, meats) or diarrhea (large amounts of fruits high in fructose) (Chart 3).

What should I drink and eat if I am SEVERELY dehydrated?

If you have severe dehydration (>6% loss of body weight) and you are not severely affected, you can drink appropriate fluids from the Chart 2 (1.5 x amount of weight loss; 1/2 amount in the first 4 hours, 1/2 in the next 8 hours) and eat usual (salty) foods to replace lost sodium 5. Sodium helps to retain water in your body. When you have no salty foods available, you can drink sport drinks, which contain sodium.

Recommended foods include complex carbohydrates (bread, saltine crackers, noodles, rice, oatmeal or other cereals), and proteins (lean meats). Avoid fatty foods, such as chocolate and red meats, and sugary foods, such as sweets and 100% fruit juices, which can slow down gastric emptying and thus water absorption.

When you experience any complications of dehydration, such as impaired consciousness, vomiting, muscle cramps or seizures, visit a doctor as soon as possible, because you may need intravenous fluid infusion.

Hyponatremia due to Excessive Drinking (Water Intoxication)

During prolonged excessive sweating (marathon, military training), an individual can lose quite some sodium from the body. When such a person replaces lost fluid by drinking excessive amount of beverages with little or no sodium (plain water, cola), he or she may develop hyponatremia (low blood sodium levels). Symptoms include vomiting, muscle weakness, confusion, seizures and, eventually, coma or death 4. Causes of excessive drinking (polydipsia)

Blood and Urine Tests in Dehydration

A doctor may order blood and urine tests to evaluate the extent of dehydration and to find the underlying cause.


  • Osmolality:
    • Normal (isotonic dehydration) in most cases
    • Increased (hypertonic dehydration): diarrhea in infants, water deprivation
    • Decreased (hypotonic dehydration): rarely
  • Sodium:
    • Normal: in most cases of dehydration 15
    • Increased (hypernatremia): water deprivation, profuse sweating, diarrhea in infants 16
    • Decreased (hyponatremia), rarely, after drinking plain water during prolonged exercise with excessive sweating (marathon) 16
  • Chloride:
    • Decreased: vomiting
  • Potassium:
    • Normal: often
    • Increased (hyperkalemia): sometimes may be triggered by dehydration; it can be also present in acute or chronic kidney failure, Addison’s disease and diabetes 1, or destruction of the red blood cells in burns 18,19.
    • Decreased (hypokalemia) due to fasting, starvation, anorexia nervosa, repeated vomiting, diarrhea, excessive urination or polyuria (in untreated diabetes 1), drugs (diuretics, high insulin doses, beta-agonists [epinephrine, isoproterenol], antibiotics, antiretrovirals, abuse of stimulant laxatives) 1.
  • Increased BUN and creatinine levels and increased BUN/creatinine ratio (>20) are sign of decreased kidney function (in severe dehydration) 8,9.
  • Glucose:
    • Increased: in untreated diabetes mellitus
    • Decreased: in severe malnutrition, diabetics (overdose of insulin or oral hypoglycemic drugs), heavy alcohol drinking without eating, adrenal insufficiency (Addison’s disease) 13,14
  • Ketones:
    • Slightly increased (ketosis) in low-carbohydrate diet or starvation
    • Severely increased (ketoacidosis) in diabetes mellitus
  • pH:
    • Decreased (acidosis) in severe dehydration resulting in decreased tissue perfusion and accumulation of lactic acid in the blood 9
    • Increased (alkalosis): vomiting 20
    • Bicarbonate decrease (base deficit) may correlate with severity of dehydration 17
  • Albumin: may be increased 10
  • Hematocrit (HCT), which is the percent of volume of the red blood cells in the whole blood: increased 10
  • Hemoglobin (Hb): increased 10
  • Platelets: may be increased 10
  • Liver panel tests (enzymes): increased AST, ALT and LDH are increased in liver damage 11.


  • 24-hour urine volume is decreased.
  • Urine specific gravity is usually increased (may be decreased in polyuria due to diabetes insipidus), but this is an unreliable sign of dehydration.
  • Ketones:
      • Low concentration: 22,25: Possibly in any case of moderate or severe dehydration (due to lower amount of urine and therefore higher concentration of ketones — this is considered false positive, because there is no actual increase in the amount of ketone excretion), low-carbohydrate diet or starvation, strenuous exercise, prolonged vomiting
      • High concentration: diabetic ketoacidosis in diabetes 1, but rarely in diabetes 2 21,22.

Possible Electrolyte Imbalances Due to Various Causes of Dehydration

Excessive Sweating

  • Hypernatremia (but in most cases normo-natremia) 29
  • Possible slight drop of potassium levels 31

Water Deprivation

  • Hypernatremia 30

Vomiting from the Stomach

  • Hypochloremia and metabolic alkalosis (vomiting of acid from the stomach)
  • Hypokalemia (kidneys excrete potassium in reaction to alkalosis)
  • Hyponatremia
  • High HCO3
  • Low CO2
  • References: 20,26

Vomiting from the Small Intestine

  • Hypochloremia and metabolic acidosis (loss of alkaline bile and pancreatic juice)
  • Hyponatremia
  • Low HCO3
  • References: 20,26


  • Hypokalemia (common)
  • Hyponatremia (common)
  • Metabolic acidosis (common)
  • Hypernatremia or hyperkalemia (rare)
  • Hypocalcemia can develop in severe diarrhea 32.
  • References: 26,27,28

Some explanation of lab tests: pathophysiology and types of dehydration

Management of SEVERE Dehydration

Intravenous Fluid Infusion (“I.V.”)

In severe dehydration, you may need intravenous fluid infusion, which is given either in the arm vein in one or both arms or in the neck vein 7. The type, amount and rate of the infusion depends on the type and severity of dehydration.

  • Isotonic solutions, such as 0.9% solution of sodium chloride [saline] also called physiological solution, or lactated Ringer solution, are the most common solutions used for treatment of isotonic, hypertonic or hypotonic dehydration 7.
  • Hypertonic solution, usually 3% saline, can be used in some cases of hypotonic dehydration 7,23.
  • Hypotonic solution, such as 0.45% saline (with or without 5% glucose), or 2.5% or 5% dextrose solution, can be used in some cases of hypertonic dehydration (diabetic ketoacidosis with hyperglycemia) 23,24
  • Potassium or magnesium may be added to intravenous solution when needed (in hypokalemia or hypomagnesemia).

For the information about indications, contraindications, dangers and the infusion rate check references 7 and 23.

Complications of Intravenous Infusion

  • When infusion is too slow, the patient may die from complications of dehydration.
  • When infusion is too quick, especially in chronic hyponatremic dehydration, a severe and commonly deadly neurological complications may occur 7.

Are there any natural remedies to cure dehydration?

Regular beverages and foods high in water (fruits) are considered natural remedies to cure dehydration. No vitamins are usually used in treatment of a dehydrated person with normal blood vitamin levels.