What is Dehydration?

Dehydration is an imbalance of fluids in the body whereby more water is excreted than is taken in. This can occur when a person does not drink enough fluid, or when excessive fluid is lost due to vomiting, diarrhea, and other illness.

Our bodies are continually losing fluids via sweat, urine, breathing, etc. These fluids are replaced when we eat and drink, and the body naturally balances input and output as needed. Minerals in the body, such as sodium, potassium and chloride, help to keep a healthy fluid balance.

Dehydration can happen slowly or quickly, depending on how the fluid is lost and the age of the child. Younger children and babies are more likely to become dehydrated than older children. This is because their bodies are smaller and they have smaller fluid reserves. Older children and teens can more easily handle minor fluid imbalances.

Signs & Symptoms

Common signs and symptoms of dehydration include:

  • dry, cracked lips and dry mouth
  • a decrease in normal urine output, no urine for eight to 12 hours, or dark-coloured urine
  • a decrease in sweat production
  • drowsiness or irritability
  • cold or dry skin
  • low energy levels or weakness

Clinical Dehydration Scale1

0 1 2
General Appearance Normal Thirsty, restless, or lethargic but irritable when touched Drowsy, limp, cold, sweaty
Eyes Normal Slightly sunken Very sunken
Mucosal Membranes* Moist Sticky Dry
Tears Present Decreased Absent

* Mucous membranes include the moist lining of the mouth and eyes.
Score: 0 = no dehydration
Score: 1-4 = some dehydration
Score: 5-8 = moderate-to-severe dehydration


First Aid for Dehydration

Treatment for dehydration is based on the degree to which a person is dehydrated.

Moderate to severe dehydration (Score: 5-8)
Seek medical help as soon as possible.

Mild dehydration (Score 1-4)
Provide the person with a non-carbonated fruit juice or sports beverage to replace the water and salts they have lost. For younger children, oral rehydration solutions such as Pedialyte, Gastrolyte, Enfalyte or other brands contain a properly balanced amount of water, sugars and salts to help the body absorb the fluid. Continue to monitor their condition and seek medical help if their condition worsens.

Water alone is not enough as it lacks sugars and salts (electrolytes) which are needed for the body to absorb fluid.

No dehydration (Score 0)
Ensure adequate intake of fluids regularly during activity and in hot weather.


Preventing Dehydration

Dehydration can be prevented by ensuring adequate fluid intake and proper nutrition. Water is typically enough to maintain hydration if the body receives the required minerals from food. Caffeinated and carbonated beverages can increase fluid-loss, so it's best to avoid these during physical activity.

Adapted from:
Dehydration. SickKids.

1 Goldman, RD., Friedman, JN. and Parkin, PC. Validation of the clinical dehydration scale for children wih acute gastroenteritis. J Pediatr, 2008. 122(3):545-9.