Dehydration Symptoms

By Dr. Ananya Mandal, MDReviewed by Sally Robertson, B.Sc.

Dehydration is caused by an inadequate intake of fluid to replace the amount that has been lost by the body. Depending on the severity of this imbalance, symptoms may be mild, moderate or severe. The severity of the dehydration depends on various factors including the underlying cause, a person’s body weight, their physical activity level, their general state of health and the climate.

Some of the symptoms associated with dehydration include:

• Thirst is often the first sign of dehydration. The thirst centres in the brain are stimulated which triggers the feeling of thirst.
• Dizziness or light-headedness
• Headache is a commonly associated with dehydration associated with alcoholism, especially during a hangover.
• Fatigue or excessive tiredness and exhaustion.
• Dryness of mouth, lips and a lack of tears, especially among children and infants
• Dark colored and potent smelling urine. The frequency of urination is reduced and there may be no urination for prolonged durations.
• Prolonged dehydration affects kidney function and may lead to the development of stones.
• Long-term dehydration can also lead to complications such as liver, joint and muscle damage.
• Dehydration over long periods leads to increased blood cholesterol.
• Bowel movements may be affected in prolonged dehydration and constipation may develop.

Severe dehydration

Severe dehydration is a medical emergency and is fatal if not promptly treated in hospital with intravenous fluids.

Symptoms of severe dehydration include:

• Dizziness and loss of consciousness
• Confusion
• Not passing urine for 8 hours or more
• Dry mouth
• Sunken eyes that do not produce tears
• Dry skin that only returns to its original position slowly after pinching
• Rapid heart rate and weak pulse
• Low blood pressure
• Irritability
• Presence of blood in vomit and stools
• Cold hands and feet
• Seizures
• Low level of consciousness

Further Reading

• All Dehydration Content
• Dehydration - What is Dehydration?
• Dehydration Treatment
• Causes of Dehydration
• Dehydration in Children