Water Intoxication: What Happens When You Drink Too Much Water?
Exploring the Risks and Consequences of Excessive Water Intake
Medically reviewed by Amelia MacIntyre, DO
Water intoxication, also known as water poisoning, is when you drink more water than your body can process. Drinking too much water by accident is difficult, but it can happen, usually from drinking excessively while participating in sports or intense training.
Symptoms of water intoxication can be nonspecific (vague) and may include confusion, disorientation, nausea, and vomiting. In rare cases, it can also cause brain swelling, which can become fatal.
This article reviews the potential causes of water intoxication, signs, and treatment.
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What Happens If You Drink Too Much Water?
Drinking too much water can result in water intoxication. Overhydration occurs when the body's volume of water becomes more than the kidneys can process and excrete. It can lead to an imbalance of electrolytes (minerals in the blood and other body fluids that carry an electric charge), such as sodium (salt).
Sodium helps maintain water balance in and around the body's cells. The balance is important for muscle and nerve function and maintaining blood pressure levels. When sodium levels are diluted in the blood (hyponatremia), fluids move from the blood to the cells.
This increase of water within the cells can lead to various health problems.
Signs You Are Drinking Too Much Water
Signs and symptoms of drinking too much water can be hard to pinpoint, especially if they occur gradually over time. Signs and symptoms may include:
Clear or colorless urine
Drowsiness or fatigue
In severe cases, water intoxication can lead to seizures or a loss of consciousness.
What Causes Water Intoxication?
Water intoxication in healthy people is rare, though it can happen. Drinking too much water is one common cause, though certain medical conditions and improper rehydration can lead to water intoxication, as well.
Sports
Endurance athletes, such as those who participate in marathons (26.2-mile run or walk), ultramarathon (longer than a marathon run or walk), Ironman or triathlon events (run, bike, and swim), hiking, or elite rowing, may be at risk for water intoxication if they drink large amounts of water prior to and during physical activity.
Drinking a lot of water after prolonged exercise repletes water reserves, but does not correct electrolyte losses that occurred during exercise. This can result in electrolyte imbalances in the blood, leading to water intoxication.
Military Training
Military members involved in intense training exercises may experience water toxicity the same as endurance athletes or people who engage in highly intense sports.
Drug Interactions
Some drugs may make you extremely thirsty and cause hyponatremia.
These include:
3,4-methylenedioxymethamphetamine (MDMA, also known as ecstasy or molly) and other phenethylamines
Antipsychotic drugs (reduce symptoms of psychosis, which affects the mind)
Diuretics (medications that reduce fluid buildup)
Mental Health Conditions
Craving water excessively due to a persistent sensation of thirst is known as psychogenic polydipsia. For example, this is sometimes seen in people with schizophrenia.
Can You Die From Drinking Too Much Water?
Though rare, there have been reported cases of people dying from drinking too much water. Electrolyte imbalances that are severe or prolonged, it can lead to seizures, loss of consciousness, and coma. Swelling of the brain may then occur and can be fatal if not promptly treated.
How Much Water Is Too Much?
There isn’t a set amount of water that is too much for the general population. A person’s age, sex, health status, and physical activity levels all play a role in determining how much water their body can process.
The kidneys of a healthy adult can process around 20 to 28 liters (5 to 7 gallons) of water in a day, with the ability to excrete only 0.8 to 1 liter per hour (27 to 33 fluid ounces). Because of this, water intake in healthy adults should not exceed this amount.
Water intoxication can happen more quickly in older adults, children, or those with certain medical conditions such as kidney disease or heart failure. This is because their kidneys may not be as efficient in processing a higher volume of water. The amount of water they can safely drink may be lower.
Always consult a healthcare provider for guidance on what amount of water is safe for you per day.
How Much Water Do You Need Each Day?
There is no official recommendation for how much plain water everyone should drink per day. However, in 2005 the Institute of Medicine released a dietary reference intake for water consumed from all beverages and foods in a day.
The recommended amounts vary depending on your age, sex, pregnancy status, and lactation (breastfeeding or chestfeeding) status. For example, the adequate intake (AI) for total water intake (from all beverages and foods) for men and women ages 19 to 30 years is 3.7 liters and 2.7 liters per day, respectively.
In general, it’s best to drink to thirst (drink when you feel thirsty). The color of your urine can also be a good indicator of hydration status. Aim for urine color that is pale yellow or the color of lemonade. Clear urine may indicate you are drinking too much water, or don’t need to drink any more water for a little while.
For some people, drinking half your body weight (in pounds) in ounces may be a good starting point. For example, someone who weighs 200 pounds might want to aim for 100 ounces of water per day.
However, keep in mind that this is not an official recommendation but rather a general rule to help guide water intake per day. Individual water needs will vary from person to person depending on other factors such as age, sex, health status, temperature conditions, and activity levels.
While drinking enough water per day is important, staying within the recommended range can help prevent overhydration and possible water intoxication.
A Note on Gender and Sex Terminology
Verywell Health acknowledges that sex and gender are related concepts, but they are not the same. To accurately reflect our sources, this article uses terms like “female,” “male,” “woman,” and “man” as the sources use them.
How Is Water Intoxication Treated?
Treatment for water intoxication will depend on the severity and the underlying cause. Along with treating any underlying cause(s), water intoxication treatments may include:
Fluid restriction
Electrolyte replacement
Diuretic medication to increase urination
Medical interventions in severe cases
Summary
Water intoxication is when you drink more water than your body is able to process. Water intoxication is rare. Causes of water intoxication include drinking large amounts of water with extreme activity, taking certain medications, or having certain medical conditions.
Signs and symptoms can be vague but may include clear or colorless urine, headache, nausea and vomiting, confusion or disorientation, muscle cramps, and drowsiness or fatigue.
Water intoxication treatment will vary depending on the severity and underlying cause and may include fluid restriction, electrolyte replacement, medications to increase urination, or other medical interventions in severe cases.
How much water you can safely drink in a day depends on several factors, such as age, sex, weight, health status, and activity levels. Urine color may be a good indicator of hydration status, with a goal of having pale yellow urine. Always talk with a healthcare provider for more individualized water intake recommendations.
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