Excessive thirst (polydipsia), frequent urination (more than eight times per day), and increased urine production (polyuria) (generally considered urine output of over 3 liters [about 100 ounces or 12.5 cups] per day) are classic symptoms of diabetes mellitus, resulting from the effects of “>high blood glucose. They are also symptoms of a dangerous complication of diabetes called diabetic ketoacidosis. To understand the cause of these symptoms, it’s necessary to understand a little about the role and function of the kidneys. The role of the kidneys is to filter waste out of the blood and maintaining a balance of chemical elements in the blood. The waste products that the kidney removes from the blood are sent to the bladder, which produces urine, which in turn is passed out of the body.1,2
The dangers of ongoing kidney strain
Uncontrolled diabetes with high levels of blood glucose can place a great deal of stress on kidney function and over time and can ultimately cause kidney disease (also called nephropathy). Excessive thirst, frequent urination, and increased urine production are signs that the kidney is working overtime to filter high levels of glucose out of the blood. To accomplish this, the kidneys produce a high volume of urine, which results in an increase in the frequency of urination and the need to urinate at night (this is called nocturne).1
Because of extra urine production, the body becomes easily dehydrated, resulting in excessive thirst. Often, an individual who experiences excessive thirst will consume carbonated drinks containing sugar to satisfy this thirst, a choice that results in a worsening of symptoms. Despite the efforts of the kidney to meet extra demands of filtering glucose out of the blood, over time high blood glucose damages the very filtering mechanism that allows the kidney to carry out its job. This is why uncontrolled diabetes is often associated with a decrease or loss of kidney function.1
Symptoms in older people
As a person ages, the capacity of their kidney to absorb excess glucose increases. Therefore, in an older person, the symptoms of thirst, increased frequency of urination, and increased volume of urine may only become apparent with higher blood glucose levels. In fact, as a person ages, the threshold for experiencing sensation of thirst increases. This means that an older person with high blood glucose is at higher risk for becoming dehydrated than a younger person and at higher risk of developing hyperosmolar syndrome.3
Learn more about hyperosmolar syndrome.
What should I do if I experience these symptoms?
If you experience these classic symptoms of diabetes and you have not been diagnosed with diabetes, you should see your doctor and discuss your symptoms. Your doctor will evaluate you and identify the cause of these symptoms. 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 diabetes, these symptoms are signs that your blood glucose is out of control. Your doctor will work with you to help you control your blood glucose, using lifestyle modifications, including a healthy, calorie-appropriate eating plan, regular physical activity, and weight loss, and, if these modifications are not enough, medication.
Learn more about medications that I can use to help control my blood glucose.