Excessive thirst is an abnormal feeling of always needing to drink fluids.
Drinking lots of water is healthy in most cases. But the urge to drink too much may be the result of a physical or emotional disease. Excessive thirst may be a symptom of high blood sugar (hyperglycemia). It can be an important clue in detecting diabetes.
Excessive thirst is a common symptom. It is often the reaction to fluid loss during exercise or to eating salty foods.
Causes may include:
- A recent salty or spicy meal
- Bleeding enough to cause a large decrease in blood volume
- Diabetes insipidus
- Medicines such as anticholinergics, demeclocycline, diuretics, phenothiazines
- Loss of body fluids from the bloodstream into the tissues due to conditions such as severe infections (sepsis) or burns, or heart, liver, or kidney failure
- A mental disorder called psychogenic polydipsia
Because thirst is the body's signal to replace water loss, it is most often appropriate to drink plenty of liquids.
For thirst caused by diabetes, follow the prescribed treatment to properly control your blood sugar level
When to Contact a Medical Professional
Call your health care provider if:
- Excessive thirst is ongoing and unexplained.
- Thirst is accompanied by other unexplained symptoms, such as blurry vision and fatigue.
- You are passing more than 5 quarts (4.75 liters) of urine per day.
What to Expect at Your Office Visit
The health care provider will get your medical history and perform a physical exam.
The provider may ask you questions such as:
- How long have you been aware of having increased thirst? Did it develop suddenly or slowly?
- Does your thirst stay the same all day?
- Did you change your diet? Are you eating more salty or spicy foods?
- Have you noticed an increased appetite?
- Have you lost or gained weight without trying?
- Has your activity level increased?
- What other symptoms are happening at the same time?
- Have you recently suffered a burn or other injury?
- Are you urinating more or less frequently than usual? Are you producing more or less urine than usual? Have you noticed any bleeding?
- Are you sweating more than usual?
- Is there any swelling in your body?
- Do you have a fever?
Tests that may be ordered include the following:
- Blood glucose level
- CBC and blood differential
- Serum calcium
- Serum osmolality
- Serum sodium
- Urine osmolality
Your provider will recommend treatment if needed based on your exam and tests. For example, if tests show you have diabetes, you will need to get treated.
A very strong, constant urge to drink may be the sign of a psychological problem. You may need a psychological evaluation if the provider suspects this is a cause. Your fluid intake and output will be closely watched.
Increased thirst; Polydipsia; Excessive thirst
Pfennig CL, Slovis CM. Electrolyte disturbances. In: Marx JA, Hockberger RS, Walls RM, eds. Rosen's Emergency Medicine. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 125.
Review Date 1/31/2015
Updated by: Linda J. Vorvick, MD, medical director and director of didactic curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.