One symptom of diabetes is feeling unusually thirsty.
Anyone who is experiencing the following symptoms should see a doctor:
What is excessive thirst?
Age, lifestyle, and activity levels can contribute to how much a person drinks.
According to the Centers for Disease Control and Prevention (CDC), there are currently no guidelines about how much water a person should drink each day.
In 2004, the Institute of Medicine estimated an adequate daily water intake as 3.7 liters for males and 2.7 liters for females. These amounts included water from all the drinks and foods in a person’s diet.
According to the National Health and Nutrition Examination Survey, 2009–2012, males in the United States tend to consume 3.46 liters of water per day, while females in the country typically consume 2.74 liters per day. These figures also included water from all dietary sources.
However, from day to day, a person may feel more or less thirsty for a variety of reasons. Spending time in the sun or being especially active, for example, can contribute to thirst.
Diabetes that causes excessive thirst
Different types of diabetes can cause excessive thirst.
The term “diabetes mellitus” includes diabetes types 1 and 2.
A person with type 1 diabetes is unable to produce insulin.
Someone with type 2 diabetes is able to produce insulin, but their body is unable to use it effectively to help glucose enter cells.
In either case, glucose from digested food remains in the bloodstream.
As the authors of a 2014 article note, the kidneys excrete some excess glucose through urine. As the glucose draws water into the urine, the body loses more fluid than it should. This results in the person becoming extra thirsty.
Gestational diabetes occurs during pregnancy.
Just as in a person with diabetes mellitus, in a woman with gestational diabetes, insulin resistance can lead to hyperglycemia.
For the reasons that we describe in the section above, this can lead to an increased need to urinate and excessive thirst.
Diabetes insipidus is a rare condition that involves the kidneys passing an unusually high amount of urine, which is diluted and odorless.
Typically, the kidneys pass about 1–2 quarts of urine a day. In someone with diabetes insipidus, the kidneys can pass 3–20 quarts a day. This results in the person being excessively thirsty.
Unlike a person with diabetes mellitus, someone with diabetes insipidus has normal blood glucose levels. However, their kidneys are unable to balance the amount of fluid in the body.
This can happen for a number of reasons, including:
- damage to the hypothalamus or pituitary gland, two small parts of the brain
- inherited genetic mutations
- an abnormality in the thirst mechanism
- transient gestational diabetes insipidus, which occurs during pregnancy
The factors above can disrupt the function of the hormone vasopressin. This hormone works with the brain and kidneys to help regulate fluids in the body.