The Relationship Between Diabetes and Thirst

The relationship between diabetes and thirst can only be best understood if one has a proper knowledge of the pathophysiology of the disease. The desire to drink water most of the times is one of the indications that one could have the disease.

Water is needed for the body’s metabolic activities; it also provides a soothing environment for the body cells. It is maintained in the interstitial and intercellular spaces, and also assists the body to eliminate some products of metabolism. As a result of this activity of helping to eliminate waste products, it needs to produce urine which is the vehicle for the bye products to be transported out of the kidneys.

However, when there is diabetes mellitus, glucose (with high molecular weight) is excreted out of the body through the urinary system. As the blood glucose level rises, it leads to impairment in the renal tubular re-absorption mechanism for glucose. This leads to some sugar being excreted in the urine.

This excretion of glucose in urine, known as glucosuria, occurs when its level exceeds 180mg/100ml of blood. Water is excreted as glucose is eliminated from the body. Its high molecular weight leads to the formation and excretion of high quantity of urine, a condition known in medical parlance as polyuria.

Since water is vital for the maintenance of the body’s metabolic activities, the body tries to compensate for this loss by sending a message to the brain which in turn stimulates the desire to drink water. So the individual feels thirsty most of the times (Polydipsia) as a way of replacing the fluid lost through frequent, excessive urination.

More often, the quantity of fluid the individual takes is not enough to compensate for this frequent loss. This brings about increased thirst; and when the fluid intake eventually becomes inadequate, the individual becomes dehydrated.

Since the renal tubular re-absorption mechanism is overwhelmed, the individual is unable to control the frequency with which urine is produced; he/she passes urine several times during the day and at night this also leads to a disturbance in his sleep as he has to get up several times to ease himself.

Just as the individual loses fluid through frequent urination, he also feels thirsty involuntarily as a way of creating a balance between intake and output. This explains the reason why the there is uncontrollable thirst in diabetes.
It is therefore advisable for you to check your blood sugar level the moment you begin to feel you are having an unusual thirst, especially if it is also accompanied by frequent or excessive urination.