How do I fix water intoxication?

December 16, 2025 •

4 min read

According to a study on Boston marathon runners, 13 percent finished the race with some degree of hyponatremia, a condition caused by water intoxication. Knowing how to respond to this potentially life-threatening condition is critical for safety.

Quick Summary

Water intoxication, or hyponatremia, occurs from overconsuming water, diluting blood sodium levels. Mild cases may involve fluid restriction and electrolyte replenishment, while severe instances require immediate hospital treatment with intravenous sodium solutions.

Key Points

Assess Severity: For mild symptoms like headache and nausea, stop drinking fluids and consume electrolytes; for severe symptoms like confusion, call emergency services immediately.
Restrict Fluid Intake: The first step in any mild overhydration case is to stop consuming water and other fluids until symptoms subside.
Replenish Electrolytes: In mild cases, consuming salty foods or electrolyte drinks can help restore the proper sodium balance in the blood.
Seek Emergency Care for Severe Cases: Severe symptoms such as seizures, confusion, or loss of consciousness are medical emergencies and require immediate hospital treatment, often involving IV saline.
Prevent Excess Intake: Use your thirst as a guide, monitor your urine color, and avoid drinking more than 1 liter of water per hour to prevent water intoxication.
Consider Underlying Conditions: Individuals with certain health issues (e.g., kidney problems, heart failure) or those on specific medications should consult a doctor for personalized hydration guidelines.

Understanding Water Intoxication

Water intoxication, also known as hyponatremia, is a serious condition caused by drinking an excessive amount of water too quickly. When this happens, the sodium concentration in the blood becomes dangerously diluted. This imbalance causes cells throughout the body, particularly in the brain, to swell. Because the skull encases the brain, swelling increases intracranial pressure, leading to the neurological symptoms that define severe water intoxication. While rare in healthy individuals, it is a significant risk for endurance athletes, people with certain medical conditions, and those who take specific medications.

What are the symptoms?

The symptoms of water intoxication can range from mild and vague to severe and life-threatening. Early recognition is key to preventing complications.

Mild to moderate symptoms:
- Nausea and vomiting
- Headache
- Bloating
- Muscle cramps or weakness
- Fatigue and drowsiness
- Clear or colorless urine
Severe symptoms (requiring immediate medical attention):
- Confusion or disorientation
- Seizures
- Loss of consciousness or coma
- Altered mental status

Key Causes and Risk Factors

Water intoxication can be caused by a few different scenarios, often involving a combination of factors. The kidneys of a healthy adult can process about 0.8 to 1.0 liters of water per hour. Exceeding this rate can overwhelm the body's ability to excrete excess water. Common causes and risk factors include:

Endurance sports: Athletes in marathons, triathlons, or intense training often consume large volumes of water, sometimes exceeding their body's capacity, especially in hot weather.
Underlying health conditions: Certain medical issues can cause the body to retain water, such as congestive heart failure, liver disease, or kidney problems.
Medications: Some drugs, including certain diuretics and antipsychotics, can increase thirst or cause the body to retain fluid.
Psychogenic polydipsia: A mental health condition that leads to compulsive water drinking.
Recreational drug use: MDMA (ecstasy) can cause both intense thirst and increased water retention, creating a dangerous combination.

How to Respond to Water Intoxication

Your response depends heavily on the severity of the symptoms. For mild cases, at-home management is possible, but severe symptoms are a medical emergency requiring immediate hospitalization.

At-Home Management for Mild Cases

If a person is experiencing mild symptoms like a headache or nausea after drinking a lot of water, and they are fully conscious, you can take these steps:

Stop drinking fluids. This is the first and most critical step.
Replenish electrolytes. Eat salty snacks like crackers, salted nuts, or pretzels. You can also have a sports drink or coconut water in moderation to help restore the sodium balance.
Rest. Avoid further strenuous physical activity that could worsen the situation.
Monitor symptoms. Keep a close watch for any worsening of symptoms, especially neurological changes like confusion or disorientation.

Emergency Treatment for Severe Cases

If a person exhibits severe symptoms such as seizures, confusion, or loss of consciousness, call emergency services immediately. These symptoms indicate significant brain swelling. In a hospital setting, medical professionals will take the following actions:

Intravenous (IV) saline solution: A highly concentrated sodium solution is administered intravenously to slowly and safely raise the blood's sodium level. The rate of correction is carefully controlled to avoid complications.
Diuretics: These medications may be given to increase urination and help the body excrete excess water.
Medication adjustment: If the cause is a specific medication, the treatment plan may include stopping or adjusting the dosage.

Mild vs. Severe Water Intoxication: A Comparison


Aspect	Mild Water Intoxication	Severe Water Intoxication
Symptoms	Nausea, headache, bloating, muscle cramps, fatigue, frequent urination, clear urine	Confusion, disorientation, seizures, loss of consciousness, brain swelling, coma, death
Cause	Overconsumption of water relative to exertion level or baseline needs	Rapid, high-volume water intake; often associated with strenuous activity, medical conditions, or drug use
Onset Speed	Gradual, often developing over hours	Can be rapid, with a dramatic drop in sodium levels over a short period
First-Line Treatment	Stop fluid intake, consume salty foods or electrolyte drinks	Immediate emergency medical care, including IV sodium replacement
Prognosis	Good; symptoms typically resolve within hours with proper management	Life-threatening without prompt and correct medical intervention

Preventing Water Intoxication

Prevention is always the best approach. Following sensible hydration strategies can significantly reduce your risk. The key is to find a balance between staying hydrated and overdoing it.

Drink when thirsty. Use your body's natural thirst mechanism as your primary guide for when to drink.
Check urine color. Aim for a pale yellow color. Clear or colorless urine can be a sign that you are overhydrated and should hold off on fluids.
Mind your pace. Avoid chugging large amounts of water in a short period. For instance, do not exceed 1 liter per hour.
Balance with electrolytes. During prolonged or intense exercise, especially in hot conditions, consider alternating between plain water and a sports drink or consuming salty snacks to replenish electrolytes lost through sweat.
Consider your medical history. If you have a kidney, liver, or heart condition, or if you take medications that affect fluid balance, consult a doctor for personalized hydration advice.
Be cautious with infants. Infants under one year old do not need water, as they get adequate hydration from breast milk or formula. Giving them water can cause water intoxication.

Conclusion

Addressing water intoxication, or hyponatremia, requires understanding its causes, recognizing the symptoms, and responding appropriately based on severity. While mild cases can be managed at home by restricting fluids and consuming electrolytes, severe cases are a medical emergency requiring prompt hospital treatment. The best approach is prevention through balanced hydration practices, paying attention to your body's signals, and being aware of the specific risks associated with exercise, health conditions, and certain medications. When in doubt, especially if severe neurological symptoms appear, always seek immediate medical help. For more information on electrolyte balance, consult resources from trusted medical institutions such as the Cleveland Clinic.

Frequently Asked Questions

For severe cases in a medical setting, the fastest way to increase blood sodium is through an intravenous (IV) drip of hypertonic saline solution. For mild cases at home, consuming salty foods or an electrolyte drink can help, but this is a slower process.

Only mild cases of water intoxication with symptoms like a mild headache or nausea can be managed at home by restricting fluid intake and increasing sodium through diet or electrolyte drinks. Severe cases are a medical emergency.

Water intoxication is an excess of water causing low blood sodium (hyponatremia). Dehydration is a lack of water, which can cause high blood sodium (hypernatremia). The symptoms can sometimes overlap, making professional diagnosis crucial for severe cases.

Recovery time depends on severity. Mild symptoms may resolve within a few hours of stopping fluid intake. Severe cases requiring hospitalization may take longer, with careful medical monitoring to ensure a safe recovery.

Early signs include nausea, vomiting, headaches, a bloated feeling, and frequent urination, especially when the urine is colorless.

For most healthy, active adults, drinking a gallon (3.8 liters) of water a day is generally safe. However, factors like body weight, climate, and activity level change requirements. The key is to not drink too much in a short period and to listen to your body's thirst cues.

Call emergency services immediately if you or someone else is experiencing severe neurological symptoms, including confusion, seizures, loss of consciousness, or significant disorientation.

Yes, water intoxication can be fatal if it progresses to a severe stage without medical treatment. The resulting brain swelling can lead to seizures, coma, and death.