Dehydration Diagnosis and Treatment in Adults

By , August 28th 2013. Last reviewed 18th November 2017.

Dehydration means a loss of water from the body. Treatment of mild and moderate dehydration includes drinking plain water or other beverages.

Severe dehydration is a life-threatening condition, which requires treatment with an oral rehydration solution or intravenous fluid infusion.

How can you know how dehydrated are you?

Your physical symptoms can tell you how dehydrated you are (Chart 1) 1.

Chart 1. Dehydration Stages

Weight loss 1-3% 4-6% >6%
Urination Slightly
Little or
no urine
Urine color Pale or strong yellow Amber Dark
Skin recoil after
pinch and release
(skin turgor test)
Up to 2 seconds Delayed
(2-10 seconds)
(>10 seconds)
Mouth and lips Dry mouth Chapped lips Chapped lips

Skin Turgor Test

Skin turgor refers to the ability of the skin to return to its normal shape after being pinched and released. Skin turgor test is a quick test for dehydration.

Normally, when you pinch the skin at the back of the hand and release it, the skin should recoil immediately; any delay in skin recoil suggests dehydration (Chart 1). Skin turgor test is not reliable in elderly people and others with wrinkled skin and in the obese people and others with distended skin.

First Aid in Dehydration

How to help an adolescent or adult person who looks acutely dehydrated:

A person who is mildly to moderately dehydrated (up to 6% loss of body weight, skin turgor <10 seconds) should get plain water, tea or similar drink without alcohol or caffeine and with no or little sugar (see the Chart 2 below), but not more than 1 liter per hour. To stimulate drinking, a person who does not feel thirsty, can try a sport drink or mineral water that contains some sodium. The goal of the treatment is to regain the original body weight and excrete clear (colorless) urine.

In hot ambient, if possible, a person should lie down in a cool place with legs raised.

A person who looks severely dehydrated (>6% loss of body weight, profound fatigue) or cannot drink due to nausea or injury or has impaired consciousness should be treated by a doctor, preferably in a hospital.

Chart 2. What to drink to relieve MILD or MODERATE dehydration?

Water, herbal tea, decaffeinated coffee Any safe and clean water is fine: tap water, bottled water, including mineral and carbonated water, clean streams or lakes
Sport drinks There is nothing wrong with sport drinks as such, but they are not needed in mild or moderate dehydration. They are a bit salty, so they can stimulate drinking.
Fruit juices, soft drinks (soda, cola), iced tea Large amounts of fruit juice contains a lot of sugar that can slow down the movement of the water from the stomach to the intestine and thus inhibit its absorption. Large amounts of sugar may also trigger diarrhea.
Green or black tea, coffee, energy drinks Large amounts of caffeine can cause anxiety or 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.
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 a large amount of soup may trigger diarrhea.
Beer, cider or other weak alcoholic beverages (up to 4-5 vol% alcohol) A 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. The 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 Contaminated water can trigger diarrhea and thus worsen dehydration.
Strong alcoholic drinks (wine, liqueurs, spirits) Drinking strong alcoholic beverages will more likely make you severely drunk than rehydrated.
Seawater 33 In short: After each liter of seawater you drink, you will likely excrete about 1.5 liters of urine, which means 0.5 liters of net water loss.

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 are able to excrete 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.

Can you eat fruits or vegetables to relieve dehydration?

Most fruits contain more than 80-90% water, so theoretically, you could correct mild dehydration by eating fruits only, when no beverages are available. Note, that you can get severely bloated or get diarrhea after eating large amounts of fruits.

How much should you drink to relieve dehydration?

To properly rehydrate yourself, you may need to drink 1.5 x amount of fluid you have lost. For example, 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 27.

What is dehydration recovery time?

In moderate dehydration, it may take you more than 24 hours to rehydrate yourself, because some of the water you drink and absorb into your circulation will be excreted in the urine before it will reach your body cells 5. You need to drink until you reach your usual body weight and your urine is clear.

Diet During Dehydration Recovery (What to Eat)

When you are recovering from dehydration, you can have your usual meals. You may want to avoid foods that can cause constipation (low-fiber foods such as chocolate, French fries, meats, cheese) or diarrhea (large amounts of fruits high in fructose).

What should you do if you are SEVERELY dehydrated?

If you have symptoms of severe dehydration (>6% loss of body weight, only minimal urination) but you can walk around, try to get an oral rehydration solution from a drug store or a sport drink that contains sodium 5. Sodium helps to retain water in your body.

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

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)
  • Chloride:
    • Decreased: vomiting
  • Potassium:
    • Normal: often
    • Increased (hyperkalemia): sometimes may be triggered by dehydration; it can also be 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 signs 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 diabetes insipidus), but this is an unreliable sign of dehydration.
  • Ketones:
    • Moderately increased concentration of ketones in urine can be found 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 increased amount of ketones), but especially in dehydration associated with low-carbohydrate diet, starvation, strenuous exercise or prolonged vomiting 22,25.
    • Greatly increased concentration of ketones in urine can be found in untreated diabetes mellitus type 1 with diabetic ketoacidosis 21,22.

Electrolyte Imbalances in 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 (in severe diarrhea) 32
  • References: 26,28

Here you can check for pathophysiology and types of dehydration.

Management of SEVERE Dehydration

Intravenous Fluid Infusion (“I.V.”)

In severe dehydration, you may need an infusion of the fluid in a vein in one or both arms or in the neck 7. The type, amount and rate of the infusion depend 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 the 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

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

Are there any natural remedies to cure dehydration?

Regular beverages and foods high in water (fruits) are considered natural remedies to cure dehydration. There is no need to use vitamin supplements in the treatment of a dehydrated person with normal blood vitamin levels.