Excessive Thirst and Frequent Urination
Reviewed by: HU Medical Review Board | Last reviewed: October 2020. | Last updated: March 2023
Excessive thirst (polydipsia) and frequent urination (polyuria) are two common symptoms of type 2 diabetes. Both are signs that high blood sugar (glucose) is causing your kidneys to work extra hard to filter high levels of sugar out of your blood.1,2
Type 2 diabetes symptoms
If you have type 2 diabetes, this means your body does not use insulin well. This is a hormone that helps sugar (glucose) move into your cells so your body can use it for energy. Since there is not enough insulin to help this process, too much sugar stays in your blood.3
Feeling thirsty all the time and urinating more than normal can be symptoms that are easy to miss. However, they can be important clues that your blood sugar is not well controlled. Recognizing these symptoms can help you get the right diagnosis and treatment sooner.
Why does diabetes cause excessive thirst and frequent urination?
Your kidneys are responsible for cleaning the sugar out of your blood. Over time, they can no longer keep up with this job because there is too much sugar for them to handle. Instead, the extra sugar and other fluids from organs are removed in your urine. This process usually makes you dehydrated and leaves you feeling extra thirsty. In turn, you drink more fluids to quench your thirst, which leads to even more urination.4
This cycle places a great deal of stress on the kidneys, leading the kidneys to burn out and cause waste and fluids to build up in your blood instead of leaving your body. It eventually causes damage to your kidneys (diabetic nephropathy). This damage begins long before you have any symptoms, so it is important for people with diabetes to have regular screenings for kidney disease.2
Excessive thirst and frequent urination are also symptoms of a dangerous complication of type 2 diabetes called diabetic ketoacidosis (DKA). This happens when the body breaks down fat too quickly. The liver then processes the fat into ketones, a type of chemical, and sends them into your blood. This causes your blood to become acidic. Symptoms of DKA, including excessive thirst and frequent urination, can develop very quickly. In extreme cases, DKA can cause a person to go into a coma, so immediate medical attention is important. If you experience symptoms of ketoacidosis, call your doctor right away.5
DKA most commonly occurs in people who are sick with nausea, vomiting, and not eating. Therefore they do not take their insulin. It can also occur in people who do not know they have diabetes and their pancreas has already failed to produce the necessary amount of insulin. Illness also increases your need for insulin because your body responds by increasing blood sugar levels.6
It is important to know that high blood sugar levels in people over the age of 60 increases their risk for dehydration. Extreme thirst and dehydration caused by extremely high blood sugar levels can cause hyperosmolar syndrome, a potentially dangerous short-term complication of diabetes. The symptoms of hyperosmolar syndrome are similar to those of DKA. If you experience symptoms of hyperosmolar syndrome, call your doctor right away.7
What should I do if I experience these symptoms?
If you experience these common symptoms but have not been diagnosed with diabetes, you should see your doctor and discuss what you are experiencing. As part of this evaluation, your doctor will measure your blood glucose to determine if it is high and whether you may have diabetes.
If you have already been diagnosed with type 2 diabetes, excessive thirst and frequent urination are signs that your blood sugar is not well controlled. Talk to your doctor about a treatment plan that will help you better manage your blood sugar levels. You should also talk to your doctor about getting screened for kidney disease.2
Diabetic kidney disease can be prevented by keeping your blood sugar levels in your target range. If not treated, kidney disease can cause kidney failure, which means your kidneys have less than 15 percent of normal kidney function. Diabetes is the most common cause of kidney failure in the United States, and many people with kidney failure either need dialysis or a kidney transplant.2
Have you experienced either of these symptoms with diabetes?