What Happens When You Drink Too Much Water? (Water Intoxication)

Effects of drinking too much water

Water intoxication is a medical condition induced when too much water is consumed over a short period, as defined by Angus Whitfield in the British Journal of General Practice. Also referred to as hyponatremia or hyper-hydration, the overconsumption of water dilutes the body’s salt and electrolyte levels, which leads to a homeostatic disruption (i.e., the body’s systems do not function in proper balance) and results in several negative physical symptoms.

While water intoxication is rare, it is a severe condition and can lead to comas and even death. According to Whitfield, high endurance athletes or others who engage in intense physical activity are often most at risk for this condition as they are likely to over-hydrate in an effort to refresh themselves during exercise.

People who participate in ‘challenges’ that require drinking large quantities of water can experience water intoxication, as noted by a descriptive medical journal from Berkeley (Limpagpalli 2017).

There have also been documented cases of water intoxication caused by other underlying health conditions. There are physical conditions that cause the body to retain or improperly dispose of water, and mental conditions such as severe depression or schizophrenia which often come with self-destructive behaviors.

Mild water intoxication is treated at home by restricting water intake and introducing diuretics (substances that increase the production of urine). But, if the symptoms have become more severe, then medical intervention is necessary (Whitfield 2006).

Typically, water intoxication is not a major daily concern for average people, as they are often more dehydrated than overhydrated, according to a recent medical study from Virginia Tech University conducted by Dr. Brenda Davy from the Department of Human Nutrition (Davy 2013).

There are some methods of calculating water intake to ensure you are not drinking too little or too much water each day. These guidelines for proper water intake can help keep you hydrated at optimal levels. Which can prevent you from feeling the negative side effects of dehydration or hyperhydration.

Table of Contents

What Is Too Much Water Intake?

The amount that qualifies as too much water intake varies based on age, height, weight, and physical activity levels (Davy 2013). The standard advice from the US National Academies of Sciences, Engineering, and Medicine is that 2.7 liters for women and 3.7 liters of fluids is a healthy intake per day. Though the Mayo Clinic states that about 20% of this usually comes from food. This amount might be too much for someone or too little for someone else depending on exercise, climate, individual health, and lifestyle.

This diagram gives the standard suggestions on daily water intake based on gender.

Recommended Daily Water Intake

To more specifically determine what the best water intake for you is, use calculations based on your weight and exercise. If not exercising, divide your body weight in pounds by 2 to get your daily intake in fluid ounces. Multiply this by 29.6 to get the number in milliliters. If you do exercise, use the same formula, but add the amount of water lost from exercising by weighing yourself before and after exercise. For each pound (0.45 kg) lost, drink 16-20 oz (0.5-0.6 liters) of water.

What Are The Effects Of Drinking Too Much Water?

The effects of drinking too much water include mild issues such as excessive urination, moderate issues such as vomiting and cramps, and serious issues such as seizures that could lead to death if there is a quick short-term case of severe water intoxication. But there is not much medical evidence of the long-term effects of consistent overhydration.

Although fairly rare, doctors like Dr. Brenda Davy acknowledge that overhydration can be just as dangerous as dehydration. This is why it is important to drink the proper amount of water daily to avoid any adverse health problems.

Are There Dangerous Effects Of Drinking Too Much Water?

Yes, there are dangerous effects of drinking too much water that can become dangerous or even fatal if they lead to severe water intoxication. These include seizures, comas, brain damage, or organ failure. The video by Science Insider explains what happens in your body when you drink too much water.

What Are The Symptoms Of Drinking Too Much Water?

The symptoms of drinking too much water (water intoxication) vary in seriousness and include the following.

  1. Color of urine
  2. Bathroom trip frequency
  3. Drinking water without necessity
  4. Nausea
  5. Vomiting
  6. Headaches
  7. Fatigue
  8. Low blood sugar
  9. Muscle cramps
  10. Colorless hands, feet, and lips
  11. Drowsiness
  12. Double vision
  13. Confusion
  14. Difficulty breathing
  15. Seizures

1. Color Of Urine

The color of urine can signal water intoxication. It is an observable symptom because the kidneys and the rest of the urinary system are responsible for expelling excess water from the body, and excess water dilutes waste products that naturally have color.

According to physicians, healthy urine is typically a very light yellow color, almost clear. If your urine is dark yellow or light brown with a strong scent, it is likely that you are dehydrated. Conversely, if your urine is as colorless and clear as water, you may be overhydrated. The color of urine is one of the best indicators of hydration levels in the body, so assessing it can let you know whether to drink more or less water. The chart below provides a guide to assessing your urine’s color to find out your hydration status.

This chart shows how to determine your hydration status based on the color of urine.

Hydration Level Based on Urine Color

2. Bathroom Trip Frequency

Bathroom trip frequency is another one of the symptoms of water intoxication. Normal bathroom trip frequency for an adult is around six to eight times within a 24-hour period. The factors for bathroom trip frequency are hydration levels, consumption of diuretics (drinks like coffee or alcohol, or certain medicines), and/or underlying medical conditions. If you are going to the bathroom more than 10 times within a 24 hour period, it is an early signal for water intoxication. be aware that diuretics and certain medical conditions can increase urination without overhydration.

In general, if you are drinking too much water, you will likely need to go to the bathroom a lot more. Dr. Ananya Mandal, a physician and researcher in West Bengal, India, notes that urinating much more frequently than usual within a short period of time is an early symptom of overhydration and water intoxication.

If you notice yourself urinating much more frequently than normal, simply stopping drinking water for a while will reduce the possibility of water intoxication.

3. Drinking Water Without Necessity

Drinking water without need is one of the symptoms of water intoxication. Drinking water without necessity can cause water intoxication if a person rapidly drinks more than 3-4 liters. This is because the kidneys can only expel around 800-1000 ml per hour, or around 20 liters within a 24-hour period, according to a medical study conducted by the Annals of Pediatric Endocrinology and Metabolism (Joo 2013).

The optimum amount of water to drink when not exercising can be determined via the formula: Body Weight (pounds) / 2 = intake in fluid ounces (multiply by 29.6 for the number in milliliters).

To decrease the negative effects of drinking too much water which is an early symptom of water intoxication, a person should simply restrict their water intake until they notice an absence of symptoms.

Our bodies are typically great at sending us cues for what we need, including water. If you feel thirsty, it is safe to assume that you need to drink more water to be properly hydrated. But, if you do not feel thirsty, drinking water without need is a sign of overhydration and can quickly lead to water intoxication.

Just as significantly, drinking without need is also a distinct and dangerous late-stage potential side effect of water intoxication. According to Dr. Mandal, severe water intoxication often induces a state of delirium, which can lead people to think they need to consume even more water despite the onset of intoxication symptoms. Do not consume any more water and seek medical attention immediately if you notice signs of delirium in yourself or others.

4. Nausea

Nausea, stomach cramping, and other gastrointestinal discomforts are very common symptoms of overhydration which can then lead to water intoxication if too severe. Nausea occurs with overhydration and water intoxication due to the unnecessary water in the stomach.

According to Dr. Mandal, stomach pains, diarrhea, and other digestive disruptions are common inconsistent and short-term overhydration; these same symptoms are then heightened in water intoxication as the body attempts to excrete unnecessary fluids.

If you feel nauseous after drinking a lot of water during a short period of time, do not try to remedy nausea with medicines or other typical anti-nausea practices, as it may prevent the body from dispelling the excess liquid. Some foods can help though, and this image shows some of the ones which best alleviate nauseousness.

Beneficial Foods for Nausea

5. Vomiting

Vomiting is a common symptom of water intoxication and a typical outcome of nausea, as the stomach tries to empty itself of some unneeded water before it reaches the kidneys or bladder.

In order to rid someone suffering from water intoxication of their excess water, the body will try to throw up some of the unnecessary liquid. Vomiting is an undesirable symptom of overhydration, but it is a natural way to treat excessive water intake and water intoxication.

Vomiting numerous times in a short period of time could be a sign of “accelerated cerebral edema,” according to Dr. Mandal. The frequency of vomiting should be monitored and professional medical care may need to be administered in some cases.

6. Headaches

Headaches are some of the more mild and commonly reported symptoms of overhydration, but they are dangerous if too severe. Water intoxication does eventually affect the brain; people often describe feeling similarly to how they feel after excessively drinking alcohol.

But, if the headache is unbearable or persistent, it could be a sign that water intoxication is potentially damaging the brain and rest of the body. In those cases, according to Dr. Mandal, the best course of action is to go to the doctor and seek medical treatment immediately to avoid further progression.

7. Fatigue

Another more mild but still potentially serious side effect of water intoxication is fatigue. After drinking too much water too quickly, the body may become lethargic and you may notice a significant decrease in energy.

If you notice a sudden, large drop in energy, you should seek medical intervention as quickly as possible as it could be an anticipatory sign of a loss of consciousness (Mandal 2019). Comas, seizures, and death have been documented with this disease, so this symptom should be monitored closely.

8. Low Blood Sugar

Low blood sugar is common with water intoxication as the excess water dilutes the body's natural storage of nutrients and important salts. This is a moderate symptom and can be treated at home.

Taking diuretics can increase the likelihood of urination and elimination of excess water. Eating foods high in salt and/or sugar content can also aid the treatment and help prevent further progression of the condition.

The image below illustrates how quickly - on a scale of 1 to 100 with 100 being fastest - some common foods can increase blood sugar levels.

GI Levels in Foods

9. Muscle Cramps

Excessive water intake will eventually impact almost all areas of the body, including the muscles (Mandal 2019). When overhydrated, the muscles may begin to cramp or spasm, which is potentially dangerous as it can be an early sign of a seizure. If you notice this symptom, medical treatment should be sought immediately to prevent severe physical problems or even death.

10. Colorless Hands, Feet, And Lips

Colorless hands, lips, and feet are common in cases of water intoxication as there is an excess of water in the bloodstream. If you notice a lack of color in these areas without the presence of other symptoms, one potential cause is overhydration, although it could also be caused by other medical conditions. If you notice this symptom and you are also experiencing some of the other symptoms listed, it is best to seek a medical diagnosis to determine if it is water intoxication.

11. Drowsiness

While some tiredness is normal and often harmless in mild cases of water intoxication, a very rapid drop in energy in conjunction with some of the other more severe symptoms could be a sign that the condition is taking a dangerous turn.

Dr. Mandal also notes that sudden restlessness is a concerning symptom that has been seen in people suffering from water intoxication. In general, if you notice a complete and rapid change in behavior in yourself or others, this is cause for medical concern.

12. Double Vision

As mentioned earlier, water intoxication often feels similar to alcohol intoxication, especially in the ways it affects your mental processing. If you are experiencing water intoxication, your vision may become affected as it does with drinking alcohol. That is, vision may become blurry, or have a “doubled” effect.

This symptom is a sign that the water intoxication has progressed to a more severe level so if you notice a change in your eyesight (or a loss of coordination in others), seek treatment immediately (Mandal 2019).

Changes in Eyesight due to Water Intoxification

13. Confusion

Confusion or delirium is one of the more dangerous symptoms of water intoxication, as it is evidence of the condition's progression and could even cause the disease to progress further.

When people become confused or mentally affected by water intoxication, they are at significant risk of serious physical complications or even death. Medical intervention is needed quickly to prevent the possibility of a stroke or heart attack.

Another risk factor with confusion is the likelihood of delusions that cause the person to drink even more water (Lingampalli 2017). Drinking more water while in this state can speed up the progression of the condition. If you have reason to suspect overhydration in someone delirious, it may be a good idea to prevent them from drinking much water until medical assistance has arrived.

14. Difficulty Breathing

Difficulty breathing is a late-stage, severe symptom of water intoxication that can easily lead to death if not medically treated immediately (Mandal 2019). If you ever experience difficulty breathing or notice others are having difficulty breathing, it should be medically remedied as soon as possible whether it is due to water intoxication or not. If a case of water intoxication reaches that stage, it can no longer be cured with home treatments.

15. Seizures

Again, this is one of the most dangerous and severe symptoms of water intoxication. Get medical assistance right away if you or someone you know is showing signs of having a seizure. If you are with someone who is having a seizure, try to ensure they do not hit their heads or hurt themselves as they spasm.

Seizures happen with water intoxication as the muscles of the body cannot handle the high amounts of water. At this stage, according to Dr. Mandal and other medical experts, there could be life-threatening consequences if treatment is not administered immediately.

How Do Scientists Define Water Intoxication?

Scientists define water intoxication as a homeostatic imbalance. It is the depletion of some of the body’s necessary salts due to an excess of fluid that causes a variety of negative physical side effects.

According to the Berkeley Medical Journal, water intoxication is “defined as a serum sodium level of less than 135 mEq/L and is characterized as an acute neurological disturbance due to the fact that brain cells swell and disrupt normal functioning” (Lingampalli 2017).

A peer-reviewed scientific article cited in the Berkeley Medical Journal defines the condition as “excessive levels of water retained in the body, which then cause a dilution of salt and electrolytes to the point where they are no longer functional. This leads to the disruption of the kidney’s normal functioning” (Coco Ballantyne, 2007).

The severity of water intoxication varies. In mild cases, people experience nausea and/or any of the symptoms typically experienced with alcohol intoxication. If the condition is more severe, or if it continues to progress from a mild case (i.e. the person continues to drink despite the onset of water intoxication symptoms), the condition can quickly become fatal.

Water intoxication can lead to seizures, comas, organ failure (typically beginning in the kidneys), and strokes, so it is important to get medical intervention right away if you suspect you or someone you know is suffering from water intoxication.

Why Is Electrolyte Loss Related To Water Intoxication?

Electrolyte loss is related to water intoxication as the excess water dilutes the body’s natural storage of salts, including electrolytes. Certain high-TDS mineral waters or sports drinks can help athletes replace electrolytes if they suspect they are over-hydrated during physical activity. journal article from the Cleveland Clinic Foundation notes that if the water intoxication has progressed too far these drinks will not help; “the only rapid method for raising the serum sodium concentration is the administration of 3 percent saline” (Gupta 2021).

Roles of Electrolytes which Water Intoxification can Weaken

When Is Water Intoxication Common?

Water intoxication is common in scenarios with high energy, strenuous physical activity (Lingampalli 2017). Physicians generally agree that the likelihood of water intoxication may also be affected by other factors such as weather, as people tend to drink more water during very hot days. In general, some of the most common places in which water intoxication has been observed are sporting events and military training.

1. Sports Events

Athletes, particularly marathon runners, are at high risk for water intoxication as they tend to over-hydrate during physical activity. In 2002, the BBC reported that a runner died of water intoxication two days after competing in the Marine Corps Marathon race. In general, sports coaches suggest that athletes drink during races and other sporting competitions when they feel the need to, as opposed to drinking water in anticipation of dehydration.

If dehydration is a major concern for a particular athlete, they can determine the exact amount of water they should drink by weighing themselves before and after exercising. For each pound (0.45 kg) of weight lost, drink 16-20 oz (0.5-0.6 liters) of water. This is in addition to a baseline daily requirement which is calculated by dividing your body weight in pounds by 2 to get your daily intake in fluid ounces. Multiply this by 29.6 to get the number in milliliters.

2. Military Training

Because of the intensity of physical training, military personnel are at a higher risk for water intoxication. According to an article from Military Medicine by COL John W. Gardner, “the current guidelines provide for water consumption up to 1 quart per hour during times of heavy sweating, not to exceed 1.5 quarts per hour and a maximum of 12 quarts per day.”

This came in response to events at the time of the article’s publication. As COL Gardner described how “on a very hot summer day in 1995, there was an outbreak of nine cases of severe acute hyponatremia in previously healthy Marine Corps recruits at Parris Island, South Carolina. They presented simultaneously with nausea, vomiting, and confusion. Five of them rapidly developed generalized seizure activity and progressed to delirium and/or coma”.

How To Calculate Correct Water Intake

When asked how to calculate one’s correct water intake, physical therapist and clinical supervisor Jennifer Stone outlined two very basic formulas for determining how much water to drink per day based on US units of measure and dependent on weight and exercise levels.

  • If not exercising: Body Weight (pounds) / 2 = intake in fluid ounces. Multiply by 29.6 for the number in milliliters.
  • If exercising: Body weight (pounds) / 2 + Water Lost = intake in fluid ounces. Multiply by 29.6 for the number in milliliters. To determine the lost water portion of the formula, weigh yourself before and after exercising. For each pound (0.45 kg) lost, drink around 16-20 oz (0.5-0.6 liters) of water.

If you are losing more than two pounds (0.9 kg) or are exercising for many hours, you may want to consider mineral waters high in electrolytes or sports drinks to ensure you receive electrolytes as you hydrate during physical activity. There is no perfect water intake calculator, but these broad principles provide good starting guidance.

What Is The Opposite Of Water Intoxication?

The opposite of water intoxication is dehydration, which is similarly dangerous and a lot more common across the country, according to Dr. Brenda Davy from Virginia Tech.

There are not many differences between water dehydration and water intoxication in terms of how they manifest physically in the body, as both cause headaches and drowsiness in mild cases and organ failure in more severe cases. intoxication often will affect a person’s mental processing whereas those who are dehydrated are more likely to become faint.

Ultimately, mild dehydration is a more common occurrence than water intoxication, and the negative effects of frequent dehydration have often been medically observed. Studies have shown that “even mild dehydration – a body water loss of 1-2% – can impair cognitive abilities.” Therefore, it is very important to overall health to be drinking the proper amount daily. Water intoxication is a dangerous condition but is rare, while dehydration is just as dangerous and occurs much more often.

Can Water Intoxication Be Seen In Animals?

Yes, water intoxication can be seen in animals, but it is not common.

Water intoxication in dogs is rare but not impossible according to an article from the Centennial Animal Hospital in Winnipeg, Canada. Dogs - especially if they are playing outside in the heat - may drink the contents of their entire water bowl and then continue playing immediately. If they are playing in the water, they are then at high risk, as they often drink large amounts of the water they’re playing in.

Overhydration can be dangerous and becomes fatal quickly so it is important to ensure your dog is taking frequent breaks for rest during playtime. Additionally, you can track and control how much water your dog is ingesting daily. The amount can be calculated based on your dog’s weight, as illustrated below based on guidance from Emancipet Non-Profit Pet Clinics.

Dog Daily Water Intake

If you notice that your dog is bloated, uncoordinated and confused, or acting in any other unusual way after they drank a large quantity of water, it is essential to bring them to a veterinarian hospital immediately.

The treatment for water intoxication in dogs is an IV to replace the dog’s electrolytes and drugs to stop brain swelling if the disease has progressed to that stage. Water intoxication in dogs is fatal, so early detection and invention are necessary.

Can Water Intoxication Affect Babies?

Water intoxication can affect babies. According to an article in the Berkeley Scientific Journal, “Johns Hopkins Pediatric Center reported that they see at least three to four cases of water intoxication among infants every summer”.

Babies under one year of age do not require much water at all, as their formula or breast milk provides them with all the nutrients they need for proper development. In order to prevent water intoxication, parents should not give their babies water. If they do, it should be limited to 2-3 ounces (60 to 90 milliliters) and only after their hunger has been satisfied, according to pediatrician Dr. John Keating from the St. Louis Children’s Hospital Diagnosis Center.

Dr. Keating also advises that parents do not participate in pool activities or swimming lessons with their infants, as they can accidentally swallow too much water. Babies are more fragile than adults, so overhydration in infants can lead to the deadly side effects of water intoxication like seizures more quickly than in adults.

Here Science Insider gives a general overview of how hyponatremia works with babies.

How To Treat Water Intoxication?

What intoxication can be treated in some of the following common ways according to medical professionals like Doctors Mandal and Davy:

  1. Cutting back on water intake
  2. Taking diuretics to increase urine production
  3. Restoring sodium levels (this treatment often requires medical expertise)

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