©2018 WebMD, Inc. All rights reserved. eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information.

Symptoms and Signs of What Are Symptoms of Dehydration in Adults?

Doctor's Notes on What Are Symptoms of Dehydration in Adults?

Dehydration is a state of fluid deficit, or loss, in the body. It happens whenever more fluid is lost than is taken in. Fluid can be lost from the body through bleeding, sweating, vomiting, urination, or diarrhea.

Dehydration can be caused by any illness that causes

  • diarrhea or vomiting,
  • excessive sweating, injury that causes bleeding, or
  • simply by not taking in enough fluid to meet the body's demands.
  • Fever can also cause the body to lose more water than usual.

The symptoms of dehydration may be mild or severe. Symptoms associated with dehydration include:

Symptoms of severe dehydration include:

  • Breathing rapidly,
  • extremely dry skin,
  • rapid heartbeat,
  • sleepiness,
  • confusion,
  • dizziness,
  • fainting,
  • sunken eyes, and
  • not urinating

Severe dehydration is a medical emergency.

Medical Author:
Medically Reviewed on 4/29/2019


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.