The signs and symptoms of dehydration in adults range from minor to severe.

Mild to moderate dehydration may include the following:

Increased thirst

Dry mouth

Tired or sleepy

Decreased urine output

Urine is low volume and more yellowish than normal

Headache

Dry skin

Dizziness

Few or no tears

The above symptoms may quickly worsen and indicate severe dehydration with signs and symptoms are developing; severe dehydration may include the following:

Severely decreased urine output or no urine output. The urine, if any, produced is concentrated and a deep yellow or amber color.

Dizziness or lightheadedness that does not allow the person to stand or walk normally.

Blood pressure drops when the person tries to stand after lying down (low blood pressure or orthostatic hypotension)

Rapid heart rate

Fever

Poor skin elasticity (skin slowly sinks back to its normal position when pinched)

Lethargy, confusion, or coma

Seizure

Shock