Dehydration signs

Overview

Dehydration happens when your body loses more fluids than you take in. This means your body doesn’t have enough water and other fluids to work properly.

Yes, dehydration is very common, especially during hot weather, illness, or after exercise.

Anyone can get dehydrated, but it is more common in babies, young children, older adults, and people with long-term health conditions.

Symptoms

Common symptoms

• Thirst
• Dark yellow urine
• Feeling tired or dizzy
• Dry mouth and lips
• Peeing less often than usual

Symptoms in children

• Fewer wet nappies than normal
• Drowsiness or irritability
• Sunken eyes or soft spot on the head
• Dry mouth and tongue
• Crying with few or no tears

Symptoms in older adults

• Confusion or disorientation
• Difficulty walking
• Dizziness or lightheadedness
• Dry mouth, cracked lips
• Low urine output

Causes

Main causes

• Not drinking enough fluids
• Sweating too much (from exercise, hot weather, fever)
• Vomiting or diarrhoea
• Frequent urination (due to diabetes or diuretic medications)

Risk factors

• Hot weather or humid environment
• Strenuous exercise
• Illnesses like gastroenteritis
• Breastfeeding or bottle-feeding babies
• Older age (over 65)
• Chronic conditions like diabetes or kidney disease

When to see a doctor

See a doctor urgently if:

• If you or your child have symptoms of severe dehydration
• If you cannot keep any fluids down
• If you have a high fever with dehydration
• If a baby under 6 months has fewer wet nappies

Book a routine appointment if:

• If you feel dehydrated often despite drinking enough
• If you have ongoing vomiting or diarrhoea for more than a day
• If you are concerned about a child's fluid intake

Diagnosis

Your doctor will ask about your symptoms, how much you have been drinking, and any recent illnesses. They may also check your heart rate, blood pressure, and skin elasticity.

Tests that may be done

• Blood tests to check electrolyte levels and kidney function
• Urine tests to see how concentrated your urine is

What to expect at your appointment

The doctor may also examine your mouth, eyes, and skin for signs of dehydration. Most cases can be diagnosed from the history and physical exam. Simple tests can confirm how severe it is.

Treatment

Treatment depends on how severe the dehydration is. Mild cases can be treated at home by drinking extra fluids. Severe dehydration may require medical treatment such as fluids given through a vein (intravenously).

Self-care at home

• Drink small amounts of water frequently
• Use oral rehydration solutions (available from pharmacies) to replace lost minerals
• Avoid alcohol and caffeine
• Rest in a cool place if dehydrated from heat
• Suck on ice chips if you cannot take large sips

Medical treatments

If dehydration is moderate to severe, a doctor may recommend rehydration solutions or fluids given directly into a vein (intravenous fluids). This helps restore the body's balance of water and salts quickly. Hospital care may be needed for severe dehydration, especially in babies and older adults.

Living with this condition

Most people with dehydration recover fully within a day or so of drinking enough fluids. For chronic dehydration, it is important to make drinking water a habit.

Lifestyle tips

• Carry a water bottle with you throughout the day
• Set reminders to drink water, especially if you are busy or forget
• Choose water over sugary or caffeinated drinks

Diet and exercise

Eating fruits and vegetables with high water content, such as watermelon, cucumber, and oranges, can help with hydration. When exercising, drink water before, during, and after physical activity.

Mental health and emotional wellbeing

Dehydration can affect your mood and concentration. You may feel tired, irritable, or find it hard to focus. Staying hydrated can help you feel better mentally.

Prevention

Yes, dehydration is usually preventable. Drink enough fluids throughout the day, especially in hot weather or when active. Pay attention to signs like thirst and urine colour.

Complications

If left untreated

• Kidney stones or urinary tract infections
• Heat exhaustion or heatstroke
• Seizures due to electrolyte imbalance
• Kidney failure in severe cases

Long-term outlook

With early treatment, most people recover completely from dehydration. Even severe dehydration can be treated successfully if medical help is received in time. Staying hydrated is key to good health.

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