Consuming the right amount of water

Periodically, the public is bombarded with articles describing people who drank too much water and suffered serious consequences leading to questions from patients wanting to know “How much water is the right amount” and “How much is too much?”

Most people have heard of dehydration, which is what happens to “Mad dogs and Englishmen” out in the noonday sun (in Malaya according to Noel Coward in 1932). The symptoms of dehydration, include thirst, dry mouth, diminished urinary output with darkened urine color from amber to brown, weak rapid heartbeat, restlessness, irritability, confusion, anxiety, weakness, inability to stand and eventually, unconsciousness.

The dehydrated person is thirsty but drinking large quantities of water can be harmful because dehydration is often associated with salt loss from sweating.

When plain water is given to such a person, depleted of both salt and water, the danger of water intoxication is great because the salt still in the body becomes diluted resulting in abnormal functioning of the brain, heart and muscles. This condition is known as over-hydration and its symptoms include nausea, dizziness and confusion, making it difficult to distinguish from dehydration.

Scientific studies of marathon runners have shown that many athletes drank too much water during the race causing a condition known as hyponatremia: “Hypo” means too little, “Natr” means salt or sodium and “Emia” means in the blood.

In the past, marathoners had been encouraged to drink as much as they could before they became thirsty. It didn’t matter whether they drank water or “sports drinks”; the problem was the same, the volume consumed was more than their kidneys could handle. The right amount of fluids for the athlete to consume is about the same as the volume of sweat produced during the strenuous activity.

Weight measurements keep track of sweat loss and Red Cross stations positioned every mile throughout the second half of marathons are equipped with scales for this purpose. Increasing weight signals that too great a volume of fluids has been consumed.

For the average healthy person, who is not a marathon runner, there is no scientific rationale to drink a lot of water. Healthy people walking around with water bottles all day are kidding themselves. Normal healthy people should drink when they are thirsty.

However, people who live in hot dry climates or those who now have or once had kidney stones (about 10 percent of the population) are well advised to increase their water intake. But, the question remains, “How much is too much?” For the stone former, drink water but never more than four quarts a day. Usually three quarts daily suffices.

Remember that with Niagara Falls pouring through your kidneys, it’s hard for a microscopic urinary crystal to stay in place long enough to enlarge and become a kidney stone so out it goes on the next urination.

Have a Question? Call Dr. Okun at 718-241-6767

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