Too Much of a Good Thing: Why You Shouldn’t Drink Too Much Water


The typical problem we hear about is not drinking enough water. It’s hard to meet the prescribed eight glasses of water a day when you’re busy, water tastes bland, and you don’t have time to be going to the bathroom every hour. It’s become so common of a problem that we’re coming up with novel ways to remind us to replenish our lifeblood - from cell phone apps to encouragingly-marked tumblers.

But in our zeal to rehydrate ad meet that eight-glass minimum, is it possible to drink too much water?

So, can you drink too much water?

The short answer is yes, and this phenomenon is called water intoxication. When you drink too much water, the increase in body fluids causes an imbalance in your electrolyte levels inside the body, specifically sodium. This can have dangerous consequences - but it isn’t likely to happen unless you drink gallons upon gallons of water in one go. The American Chemical Society defines “too much water” as 6 litres per 165-pound person.

Regrettably, documented cases of adults drinking too much water, to fatal results, are common. A 28-year-old woman competing in a water-drinking contest in California called “Hold Your Wee for a Wii” died after consuming six litres of water in under three hours. Marathon runners are susceptible to it when they sweat out copious amounts of sodium and rehydrate too quickly with plain water. Partygoers have also died from drinking too much water after being high on ecstasy, a drug that makes you sweat a lot and get very thirsty.

Babies are more susceptible to water intoxication because their small bodies are much easier to overload with water. It is for this reason that we avoid giving water to babies and stick to milk, which is enough for both nutrition and hydration.

What happens when you drink too much water?

Water intoxication happens when you’re consuming water at a faster rate than your kidneys can flush out. This causes a condition called hyponatremia, translated from Greek and Latin as “inadequate levels of sodium in the blood.” Drinking gallons upon gallons of water doesn’t decrease your sodium levels, but it severely dilutes the blood - so much that the concentration of sodium in your blood drops below the normal level of 135-145 millimoles per litre.

Water flows towards areas of higher sodium concentration. When you drink too much water, the concentration of sodium in your blood becomes lower than the concentration of sodium inside your cells. Thus, water flows into your cells, where the concentration is higher. This makes your cells swell.

This swelling, or edema, can be fatal when it comes to your brain cells. Unlike other organs in your body, your brain is encased in the skull, which is basically a closed box made of bone. Inside the skull, there is no room for cells in the brain to swell when filled with water. When pressure inside the skull increases, the brain tissue bumps up against the walls of the skull, and blood flow and oxygen supply to the brain are cut off. This lack of oxygen in the brain can cause seizures, loss of consciousness, and if left unresolved, death.

Symptoms of water intoxication

The early warning signs of hyponatremia and water intoxication are vague, so the condition may be hard to catch. Be on the lookout for:

  • Headache
  • Fatigue
  • Nausea and vomiting
  • Frequent urination
  • Diarrhea
  • Feeling hot

Sometimes the symptoms of water intoxication resemble symptoms of heatstroke, which can be dangerous as the victim might be tempted to drink even more water. When encountering these signs, it’s wise to ask what they were doing before the onset of their symptoms, because otherwise you won’t know that they drank too much water until it’s too late!

Late symptoms of water intoxication include mental disorientation,  projectile vomiting, and coma. Seek medical help right away if you suspect water intoxication. Doctors may need to inject salt water into the patient to restore the sodium balance and reduce swelling  This condition is a medical emergency and any delay might lead to the brain edema being irreversible.

An ounce of prevention over a pint of cure

The easiest way to prevent hyponatremia from water intoxication is to simply not drink more than is necessary - definitely not entire litres of water in a short period of time! Experts say you don’t even need to stick to that eight-glasses-of-water credo because there’s already water in the food and other beverages you consume. Just drink until you no longer feel thirsty, then stop.

Balance water that you’re drinking with water you’re flushing out through urine and sweat. It’s important to note that when you sweat, you’re also excreting sodium along with water. Thus, if you replenish your water losses with plain water, you risk diluting your sodium concentration as well. Rehydrate with sports drinks when you expect to be sweating a lot to preserve the balance of sodium and fluid in your blood.

Water is necessary to the body, but too much of a good thing is never wise. As with all things, moderation is key! When it comes to water, drink only what you need, no less, and certainly no more. ■