Polydipsia: The Word for Excessive Water Intake and Its Dangers

December 4, 2025 •

4 min read

Affecting up to 20% of hospitalized patients, hyponatremia is a common electrolyte imbalance caused by excessive water intake, which dilutes the body's sodium concentration. The medical term for the underlying symptom of abnormal or excessive thirst is polydipsia, which can lead to the dangerous condition of water intoxication.

Quick Summary

Polydipsia, the medical term for excessive thirst, can lead to overhydration and water intoxication. This dangerous condition causes hyponatremia, a life-threatening electrolyte imbalance resulting from diluted sodium levels. The severity can range from headaches and confusion to seizures, coma, or even death.

Key Points

Polydipsia: The medical term for excessive or abnormal thirst leading to high fluid intake.
Water Intoxication: A dangerous condition caused by overhydration, which dilutes the body's sodium levels.
Hyponatremia: The specific medical condition of low blood sodium resulting from excessive water consumption.
Cell Swelling: The primary danger of hyponatremia is fluid moving into and swelling the body's cells, particularly brain cells.
Critical Symptoms: Severe water intoxication can cause neurological issues like confusion, seizures, coma, and even death.
Risk Groups: Endurance athletes, individuals with psychiatric conditions, and those with certain diseases are at higher risk for overhydration.
Prevention: Listen to thirst cues, monitor urine color, and consider electrolyte drinks during intense exercise to prevent hyponatremia.

What is Polydipsia?

Polydipsia is the clinical term for excessive or abnormal thirst and is a symptom of various medical disorders, not a disease itself. This persistent, unquenchable thirst drives an individual to consume excessive quantities of fluids, often far exceeding the body's needs. It is distinct from normal thirst, which is satisfied after a reasonable amount of fluid consumption.

Polydipsia can be classified into two main types:

Primary polydipsia: This refers to excessive fluid intake without an underlying physical cause. It is further divided into two subtypes:
- Psychogenic polydipsia: A compulsive water-drinking behavior often associated with psychiatric conditions like schizophrenia.
- Dipsogenic polydipsia: Excessive drinking due to a malfunction in the hypothalamus, the part of the brain that regulates thirst.
Secondary polydipsia: This type has a physical reason for the excessive thirst, such as diabetes mellitus, where high blood sugar causes increased urination, and the resulting dehydration triggers a cycle of thirst and drinking.

Medical Conditions and Medications Causing Polydipsia

Several medical conditions can cause secondary polydipsia and lead to excessive water intake. These include:

Diabetes Mellitus and Diabetes Insipidus
Adrenal gland insufficiency
Kidney or liver disease
Dehydration due to severe vomiting or diarrhea

Certain medications can also increase thirst as a side effect:

Diuretics (water pills)
Antidepressants
Antipsychotics
MDMA (ecstasy)

Overhydration and Water Intoxication

While excessive water intake (polydipsia) is the behavior, overhydration is the resulting physical state where the body has more water than it can excrete. If this imbalance becomes severe, it leads to a critical condition called water intoxication or water poisoning. The primary danger of water intoxication is its effect on the body's electrolyte balance, specifically sodium levels.

The Mechanism of Hyponatremia

Excess water consumption dilutes the blood's sodium concentration, leading to a condition called hyponatremia. Sodium is a crucial electrolyte that helps regulate fluid balance both inside and outside the body's cells. When sodium levels drop, fluids shift from the diluted bloodstream into the cells, causing them to swell. This swelling can be particularly dangerous when it affects brain cells, as they are enclosed within the skull and have no room to expand. The resulting pressure can disrupt normal brain function and lead to severe neurological symptoms.

Symptoms of Water Intoxication

Symptoms vary depending on the severity and speed of sodium decline. A rapid drop can be more dangerous than a gradual one.

Early to Moderate Symptoms:

Headache
Nausea and vomiting
Fatigue and weakness
Muscle cramps or spasms
Confusion or disorientation
Frequent urination or clear urine

Severe Symptoms:

Irritability and altered mental status
Seizures
Coma
Brain damage or swelling (cerebral edema)
Death

When Too Much Water Becomes Dangerous: A Comparison

To understand the progression of overhydration, it's helpful to compare its stages and symptoms.


Feature	Normal Hydration	Mild Overhydration	Severe Water Intoxication (Hyponatremia)
Symptom Manifestation	No unusual thirst or fatigue	Persistent thirst, frequent urination	Severe headache, nausea, confusion
Urine Color	Pale yellow	Often clear or colorless	Clear and high volume (polyuria)
Electrolyte Balance	Sodium levels within the normal range (135-145 mEq/L)	Slightly diluted blood sodium	Severely low blood sodium levels (<125 mEq/L)
Cellular Effect	Normal fluid balance	Cells begin to absorb excess fluid	Significant cell swelling, especially in the brain
Kidney Function	Kidneys efficiently process and excrete excess water	Kidneys become overwhelmed, struggle to excrete fluid	Kidneys are severely taxed, can't keep up with fluid load
Neurological Impact	Normal cognitive function	Mild fatigue, distractibility	Seizures, coma, brain damage, potential death
Risk Level	Low	Low to Moderate	High to Fatal

How to Prevent Overhydration and Water Intoxication

For most healthy adults, drinking too much water is difficult to do accidentally. The kidneys can process a significant amount of fluid, and thirst is an effective guide. However, for athletes and individuals with certain medical conditions, awareness is key.

Listen to your body: Drink when you feel thirsty and stop when your thirst is quenched.
Monitor urine color: Pale yellow urine is a good indicator of proper hydration. Clear urine, especially in high volumes, suggests you might be overhydrating.
Limit intake during intense exercise: Endurance athletes should be mindful of their water intake, especially in hot conditions. It is recommended not to drink more than about one liter per hour.
Consider electrolyte replacement: During prolonged, intense physical activity, use sports drinks or tablets to replace lost sodium and other electrolytes.
Avoid water-drinking challenges: Never participate in competitive water drinking, as it can lead to acute and fatal water intoxication.

For infants under one year, who are at higher risk due to immature kidneys, breast milk or formula provides all necessary hydration. Never give an infant large quantities of water.

Conclusion

The word for excessive water intake is polydipsia, a symptom of underlying conditions that can lead to a dangerous state called overhydration or water intoxication. This life-threatening electrolyte imbalance, known as hyponatremia, occurs when the body's sodium is dangerously diluted, causing cells to swell. While rare in the general population, understanding the causes and symptoms—from headaches and confusion to seizures and coma—is critical for prevention. By listening to your body's thirst cues, monitoring urine color, and managing fluid intake during high-intensity activity, you can stay safely hydrated. Anyone experiencing persistent, unquenchable thirst should consult a healthcare provider to diagnose and treat the root cause. For more information on hyponatremia, consult reliable sources like the Mayo Clinic's detailed guide.

Note: This article is for informational purposes only and is not medical advice. Consult a healthcare professional for diagnosis and treatment.

Frequently Asked Questions

The medical term for excessive thirst and fluid consumption is polydipsia. If this leads to a dangerous imbalance of electrolytes, it is referred to as overhydration or water intoxication.

Mild symptoms include frequent urination and clear urine. More severe symptoms of water intoxication can involve headaches, nausea, muscle cramps, fatigue, confusion, and disorientation due to low sodium levels.

There is no exact amount, as it depends on individual factors. However, healthy kidneys can only excrete about 0.8 to 1.0 liters per hour. Consuming significantly more than this over a short period, such as over 3-4 liters quickly, increases the risk of water intoxication.

Yes, in rare and severe cases, water intoxication can be fatal. This is typically caused by rapid, excessive consumption that leads to severe hyponatremia and brain swelling.

Excessive water intake can stem from psychiatric disorders like psychogenic polydipsia, medical conditions like diabetes mellitus or kidney problems, certain medications (e.g., diuretics), or intense physical activity without proper electrolyte replacement.

Drinking too much water dilutes the blood's sodium concentration, causing a condition called hyponatremia. This leads to fluids shifting into the body's cells, causing them to swell, particularly brain cells, which can lead to neurological damage.

The color of your urine is a good indicator. If you have clear or colorless urine and are also experiencing frequent urination, headaches, or nausea, you may be overhydrated. Listening to your body's thirst cues is also important.