Excessive Thirst: 12 Common Causes & What to Do

Medical review: Dr. Clarisse Bezerra
Family Doctor
November 2022

Excessive thirst is usually caused by eating salty food, intense physical exercise, hot environments or decreased water intake throughout the day. 

However, feeling very thirsty may also be a sign of a health condition like diabetes, dehydration, or even a psychiatric problem. Intense thirst can often be accompanied by other symptoms, like fatigue, headache, vomiting and increased urine production. 

You should see your doctor if you frequently experience excessive thirst or if you have thirst with other symptoms. An assessment will allow the doctor to identify the underlying cause and intiate treatment as necessary. 

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Causes of excessive thirst 

The most common causes of intense thirst are: 

1. Salty food 

Eating very salty food can cause thirst. It is the body’s natural reaction to trigger you to drink water, as fluids will help to eliminate excess salt. 

What to do: You should ideally limit your salt intake, as it can cause thirst and also increase your risk for development certain conditions, like hypertension. 

2. Not drinking enough water

Poor water intake throughout the day may cause thirst. The body needs a certain amount of water each day to carry out regular functions, and will respond if adequate water is not available for use. Blood volume can decrease, blood pressure can become abnormal and salt or mineral levels can fluctuate. These changes can be picked up by the brain, which stimulates the a thirst reaction. 

What to do: You should increase your daily water intake. The recommended amount depends on your weight and age, however 1.5 L to 2 L is generally recommended per day. Fluids can be ingested in water, mineral water, infusions or unsweetened tea forms. 

3. Intense physical exercise 

Intense physical exercise can lead to significant fluid losses, which will prompt the body to signal thirst responses. 

What to do: It is important to ingest plenty of fluids during and after working out to prevent dehydration. You should opt for electrolyte solutions, like mineral water or Gatorade to replenish electrolytes loss through perspiration. 

4. Diabetes mellitus

One of the main symptoms that emerge in people with undiagnosed diabetes is excessive thirst. This occurs because the body is insufficient at using or producing insulin. Insulin is important for transporting sugar to the cells, and malfunctioning in this process will lead to increase sugar levels in the blood. High blood sugar can increase your thirst, as this is a way for the body to dilute the amount of sugar circulating. 

What to do: If your excessive thirst is accompanied by other symptoms, like excessive hunger, weight loss, dry mouth, or frequent urination, you should see your doctor for assessment. The doctor will order testing to confirm diabetes and to confirm the type, which will guide treatment. Learn about the different diabetes medication that can be prescribed to manage diabetes. 

5. Diabetes insipidus

Diabetes insipidus is a rare condition that is caused by a decrease in ADH (antidiuretic hormone) production. This hormone control the speed at which urine is produced. This condition can also occur due to the kidneys’ decreased response to this hormone. 

Diabetes insipidus leads to a greater urine productions, fluid losses and dehydration, which contribute to thirst. 

What to do: You should see a family doctor or endocrinologist to confirm the presence of diabetes insipidus and start appropriate treatment. Treatment will depend on the underlying cause, and can involve the use of hormones, diuretics or anti-inflammatories. 

6. Pregnancy

Pregnancy can also cause excessive thirst and is a very common symptom among pregnant women. It may emerge due to the body’s need to increase circulating fluid volumes and maintain normal amniotic fluid levels. 

Excessive thirst may also be a sign of gestational diabetes. This is also a rare condition that is more frequently seen in the third trimester. HELLP can also cause thirst, and is a condition that is accompanied by other symptoms like excessive fatigue, general malaise, nausea, vomiting or headaches. 

What to do: You should ensure you are followed by an obstetrician throughout your pregnancy to monitor for these types of conditions. With HELLP syndrome, you should seek immediate medical attention so that treatment can be promptly initiated. 

7. Vomiting and diarrhea 

Episodes of vomiting or diarrhea can lead to significant fluid losses. The body will initiate a thirst response to recuperate these losses and prevent dehydration.

What to do: You should drink plenty of water after each episode of vomiting or diarrhea to ensure fluids are replenished. Read more about ways to stop diarrhea to prevent further fluid losses. 

8. Dehydration

Dehydration occurs when water levels in the body become low and the body is unable to carry out optimal functioning. It causes symptoms like excessive thirst, dry mouth, intense headache and fatigue. 

What to do: To prevent dehydration, you should ingest at least 2 L of water per day. You can opt for other fluids as well, like teas, fruit juices, milk and soup. You should also consume water-rich fruits and vegetables, as they also contribute to overall body hydration.

9. Heat and sun exposure

Staying under the sun or in a hot environment for too long can increase sweat production and lead to fluid losses. This can trigger the body’s thirst response to trigger you to drink more water. 

What to do: You are advised to use light clothing to relieve discomfort and reduce sweating. You should also drink plenty of fluids throughout the day to prevent dehydration.

10. Dry mouth

A dry mouth, medically referred to as xerostomia, is characterized by an interruption of saliva production or a change in saliva composition. It can cause the sensation of a very dry mouth which can increase thirst. 

Generally, a dry mouth is accompanied by other symptoms like foul breath, thick saliva or difficulty chewing. It is generally caused by smoking, anxiety, or other health conditions, like anemia, lupus or multiple sclerosis. 

Read more about the most common causes of dry mouth

What to do: It is important to drink plenty of water throughout the day to keep the oral mucosa moist and hydrated. You should also avoid smoking. For more severe cases, the doctor may recommend a more specific treatment, like artificial saliva or treatment targeted at a health condition causing this symptom. 

11. Psychiatric disorder

Some psychiatric illnesses, like schizophrenia, psychotic depression, and bipolar disorder, can cause excessive thirst. It is also referred to as psychogenic polydipsia and often results in excessive thirst and frequent urination. 

Due to increased ingestion of fluids and urination, sodium levels can drop, causing hyponatremia. This condition can lead to symptoms like confusion, drowsiness and vomiting. 

What to do: The psychiatric disorder should be well-managed under the direction of a psychiatrist. He or she may prescribe medications like antipsychotics, antidepressants or antidepressants. 

12. Medication

Some medications, like diuretics, lithium and antipsychotics can cause thirst as a side effect. 

What to do: To offset this side-effect, you should drink small sips of water throughout the day. In some cases, in which the thirst or dry mouth are very uncomfortable, you should report this side effect to the doctor. 

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Edited by Tua Saude editing team in November 2022. Medical review completed by Dr. Clarisse Bezerra - Family Doctor in November 2022.

References

  • KOTAGIRI, R.; KUTTI SRIDHARAN, G. IN: STATPEARLS [INTERNET]. TREASURE ISLAND (FL): STATPEARLS PUBLISHING. Primary Polydipsia. 2022. Available on: <https://www.ncbi.nlm.nih.gov/books/NBK562251/>. Access in 09 Aug 2022
  • NCHS. Daily Water Intake Among U.S. Men and Women, 2009–2012. 2016. Available on: <https://www.cdc.gov/nchs/data/databriefs/db242.pdf>. Access in 03 Mar 2020
Show more references
  • PAT, James; MCFADDEN, Roger. Understanding the processes behind the regulation of blood glucose. Diabetes Knowledge. Vol.100. 56-58, 2004
Medical review:
Dr. Clarisse Bezerra
Family Doctor
Dr. Bezerra possesses a medical degree and specializes in family medicine. She is licensed to practice under CRM-CE licence #16976.