Water, which accounts for as much as 60 percent of an adult's body weight, is vital to virtually all physiological functions. Thirst is a signal to replace some of the water the body continuously loses through processes such as sweating, breathing, and elimination of waste products. Most people need to drink about 8 glasses of water or other nonalcoholic fluids a day. The need for water tends to be greater in hot weather or after activities that cause heavy perspiration. It can also be increased by illnesses such as colds and flu.
Occasionally, thirst is a symptom of a medical problem. A doctor's attention is necessary if thirst persists despite adequate fluid intake.
Causes of thirst
Acute erosive gastritis
Acute gastritis is a poisoning emergency that usually requires immediate hospitalization. Along with excessive thirst, symptoms include severe stomach pain, rapid pulse, difficulty swallowing, and (possibly) vomiting blood.
Alcohol has a diuretic effect, which is what makes thirst a classic component of a hangover. It is common to wake with a dry mouth after drinking too much. Drink water or fruit juice to relieve the thirst.
Intense thirst can be a symptom of severe anemia, a condition in which the blood contains too few red cells or too little hemoglobin. The hemoglobin molecule is the component of the red cell that carries oxygen to the tissues of the body.
Diabetes insipidus, which is unrelated to the more common disorder diabetes mellitus, occurs when the hormone vasopressin is lacking or when the kidneys are unable to respond to it. Vasopressin prevents the kidneys from excreting too much water. The disorder may result in the excretion of several gallons of urine daily resulting in great thirst despite drinking large quantities of liquids.
Diabetes develops when the body either does not produce enough of the hormone insulin or is unable to use it. The
classic symptoms are thirst, excessive urination, and hunger.
Acute or prolonged diarrhea can cause dehydration and thirst. Prolonged diarrhea related to an intestinal infection or food poisoning can be serious enough to require intravenous fluids, especially in a young child.
Diuretics and other medications
Diuretics, commonly called water pills, increase the body's secretion of salt and water. Many people taking diuretics for high blood pressure or other conditions complain of feeling overly thirsty. Other drugs that can produce a dry mouth and thirst include antidepressants, narcotic painkillers, and tranquilizers.
A high or prolonged fever can cause dehydration and excessive thirst, especially if it is accompanied by vomiting and/or diarrhea. Increased fluid intake is recommended during a fever.
Heat exhaustion and sunstroke
Both these conditions can cause extreme dehydration. Immediate emergency care is needed to prevent shock and organ failure. Malaria
Malaria is characterized by periods of high fever and excessive sweating, both of which cause thirst.
This is an infection of the membrane that covers the
abdominal organs, which can occur in an abdominal organ, such as a ruptured appendix or gallbladder. It can also result from a faulty abortion, the leakage of blood from an abnormal pregnancy, or an infection of the female genital tract. Intense pain is a primary symptom, as well as vomiting, rapid heartbeat, fever, and thirst. Peritonitis requires emergency surgery.
Excessive perspiration can cause dehydration if the fluids are not replaced. Sweating is a normal and healthy response to heat and heavy exercise, but it also may be a symptom of disease. For example, waking at night with a drenching sweat and intense thirst may be a sign of certain cancers.
Advice about thirst
- Drink at least 8 glasses of fluids a day. Water is the best choice; coffee and tea are both mild diuretics and can increase thirst.
- Increase your fluid intake when it is hot or humid.
- Drink more fluids when you have a fever, a cold, the flu, diarrhea, or other illnesses.
- Vomiting or diarrhea lead to dehydration. The resulting thirst should be quenched, but if symptoms continue, consult your doctor.
- Sudden development of constant thirst should be reported to your doctor, as it may be a warning sign of diabetes.