Polydipsia is an excessive and sometimes constant thirst, usually leading to an increased consumption of water. The increased intake of water can be the result of many factors, including:

• Exertion
• Injury
• Illness
• Diet
• A side effect of medication

However, when increased thirst cannot be explained by lifestyle changes or temporary illness, a physician should be contacted as it may be a sign of a number of diseases and disorders, including diabetes and prediabetes. About 20.8 million Americans, 6.2 million of them undiagnosed, have diabetes, and 41 million have prediabetes, according to the U.S. Centers for Disease Control and Prevention (CDC).

Definitions of polydipsia vary. Excess intake of fluids in adults can be defined as the consumption of more than a gallon (128 ounces or 3.8 liters) of beverages a day, according to the Diabetes Insipidus Foundation.

Recommendations that people should drink a lot of water to avoid dehydration are leading some to become overhydrated, according to the Institute of Medicine. Overhydration, where the body loses less water than it takes in, causes insufficient levels of sodium in the blood (hyponatremia). Extreme cases of overhydration, or water intoxication (regularly drinking more than 2 gallons or 7.6 liters a day), can cause tissue damage, confusion, seizures, coma and even death.

Dozens of studies indicate that, generally, men need an average of 125 ounces (3.7 liters) and women 91 ounces (2.7 liters) a day, according to the Institute of Medicine, which advises consuming less sodium rather than overhydrating. Individuals who are very active physically or live in hot climates may need to drink more.

Because polydipsia often leads to excessive consumption of water, it is closely linked with polyuria (the production of large volumes of urine). Experiencing excessive thirst and possibly excessive urination does not usually constitute a medical emergency, but several potentially serious diseases may be the cause behind these symptoms.

In addition to polydipsia, polyuria and dehydration, several other symptoms can suggest diabetes. These include polyphagia, unexplained weight loss, fatigue, dizziness and fainting.