Maxy sez : Why Does Diabetes Make You So Thirsty?

By Sanjay Gupta, MD
Excessive thirst, or polydipsia, can be triggered by different factors such as eating too much salt or taking medications that cause dry mouth. Thirst is also a symptom of diabetes. For people with diabetes, thirst can be a sign of hyperglycemia, or high blood sugar.

The kidneys play a vital role in regulating levels of blood sugar by filtering the blood and absorbing excess glucose. When very high levels of sugar build up in the blood, the kidneys can’t keep up and they produce more urine than normal — a condition known as polyuria. As a result, you can become dehydrated.

“People who have well-controlled diabetes should be at no increased risk for excessive thirst compared with somebody who doesn’t have diabetes,” says Noah Bloomgarden, MD, assistant professor of medicine-endocrinology at the Albert Einstein College of Medicine and clinical endocrinologist in the division of endocrinology, diabetes, and metabolism at the Montefiore Health System in the Bronx, New York. “It’s really poor control of one’s blood sugar and an increase in urination and excretion of water that makes people [with diabetes] feel very thirsty and increases their need to maintain water balance.”

As Dr. Bloomgarden points out, even people who are doing a good job of controlling their diabetes can develop very high blood sugar. A cold, infection, or even a very stressful situation can cause blood sugar to rise, and excessive thirst may be the first sign that something is wrong. “If you’re experiencing excessive thirst, you should contact your doctor immediately, because it may indicate severe hyperglycemia,” says Bloomgarden.

If you have diabetes and you’re not sure whether you’re unusually thirsty, Bloomgarden suggests that you check your blood sugar. If your blood sugar is normal but you’re thirstier than usual (or you’re going to the bathroom more often), consult your doctor.

If you are experiencing excessive thirst related to hyperglycemia, it’s imperative to get your diabetes under control. Make sure you’re following the treatment plan prescribed by your doctor, including any lifestyle recommendations such as eating a healthy diet and exercising regularly. If you’re having trouble sticking with your treatment plan, you may benefit from consulting with a certified diabetes educator, who can help you self-manage your blood sugar.

It’s also important to make sure you’re drinking enough water, especially if your blood sugar is elevated. The Joslin Diabetes Center recommends drinking a minimum of eight glasses of water a day.

“There are no complications associated with increased thirst if people are able to drink water freely,” says Bloomgarden. But it can become a major issue if somebody is elderly or isn’t mobile and doesn’t have the ability to access water or other liquids. “Then they can get profoundly dehydrated, and that can be extremely dangerous,” he warns.


Do you have a health-related question for Dr. Gupta? You can submit it here. For more health news and advice, visit Health Matters With Dr. Sanjay Gupta.