How much water do you really need to drink?

If you’ve spent any time on social media or recently attended a sporting event, surely you’ve been bombarded with encouragement to drink more water. Most influential celebrities carry gallon-sized water bottles like the new fashion accessory. Twitter bots are constantly reminding us to spend more time hydrating. Some reusable water bottles even come with motivational phrases – “Remember your goal”, “Keep drinking”, “You’re almost done” – to encourage us to drink more fluids throughout the day.

The supposed benefits of excessive water consumption are seemingly endless, from improved memory and sanity to increased energy and improved complexion. “Stay hydrated / hydrate” has become a new take on the old “you’re fine” greeting.

Corn What exactly does “stay hydrated” mean? “When laypersons talk about dehydration, they mean the loss of all fluid,” says Joel Topf, nephrologist and associate professor of clinical medicine at Oakland University in Michigan.

But that interpretation “has been completely overestimated,” said Kelly Anne Hyndman, a kidney function researcher at the University of Alabama at Birmingham. Staying hydrated is important, he said, but the idea that just drinking more water will make people healthier isn’t true. It is also wrong to say that most people are chronically dehydrated or that we should drink water all day long..

From a medical standpoint, Topf added, the most important measure of hydration is the balance between electrolytes such as sodium and water in the body. And you don’t need to drink glass after glass of water throughout the day to keep it going.

How much water should I drink?

To all We have been taught that eight glasses of water a day is the magic number for everyone, but that notion is a myth.said Tamara Hew-Butler, exercise and athletic specialist at Wayne State University.

Unique factors like body size, outside temperature, and how much you breathe and sweat will determine how much is needed, noted. A 200-pound person who has just walked 10 miles in the heat will obviously need to drink more water than a 150-pound office manager who has spent the day in a temperature-controlled building.

The amount of water needed in a day too it will depend on your health. A person with a condition such as heart failure or kidney stones may need a different amount than when taking diuretic drugs, for example. Or a person may need to change their intake if they have been sick, vomited, or have diarrhea.

For most young and healthy people, the best way to stay hydrated is to simply drink when you are thirsty.Topf said. (Seniors, aged 70 to 80, may need to be more careful about drinking enough, as the feeling of thirst may decrease with age.)

And, despite popular belief, don’t rely on the color of urine to accurately indicate your hydration statusHew-Butler said. Yes, dark yellow or amber urine can mean you’re dehydrated, but there’s no solid science to suggest that color alone is an indication that you should drink water.

Do I need to drink water to stay hydrated?

Not necessarily. From a purely nutritional point of view, water is a better option than less healthy options, like sugary sodas or fruit juices. But when it comes to hydration, any drink can add water to your system., says Hew-Butler.

A popular notion is that consuming caffeinated or alcoholic drinks dehydrates you, but if this is true the effect is negligible, Topf said. A 2016 randomized controlled trial with 72 men, for example, found that the moisturizing effects of water, beer, coffee and tea were almost identical.

You can also get water from what you eat. Foods and meals rich in fluids, such as fruits, vegetables, soups and sauces, contribute to water intake. Additionally, the chemical process of metabolizing food produces water as a by-product, which also contributes to consumption, according to Topf.

Should I be concerned about electrolytes?

Some sports drink advertisements may make you think that you need to constantly top up electrolytes to keep your levels in check, but there is no scientific reason why most healthy people drink drinks with added electrolytesHew-Butler noted.

Electrolytes, such as sodium, potassium, chlorine, and magnesium, are electrically charged minerals that are found in body fluids (such as blood and urine) and are important for balancing water in the body. . They are also essential for the proper functioning of nerves, muscles, brain and heart.

When you become dehydrated, the concentration of electrolytes in the blood rises and the body signals that the hormone vasopressin is released, which ultimately reduces the amount of water released in the urine so that it can be reabsorbed back into the body. and regain balance, Hyndman said.

Unless you have unusual circumstances – exercising very vigorously in the heat or losing a lot of fluids through vomiting or diarrhea – you don’t need to replenish your electrolytes with sports drinks. or other products loaded with electrolytes.. Most people get enough electrolytes from food, Hew-Butler said.

But drinking more water, even when I’m not thirsty, will improve my health, right?

No. Of course, people with certain conditions, such as kidney stones or the rarer autosomal dominant polycystic kidney disease, may benefit from drinking a little more water than their thirst indicates, Topf said.

But most healthy people who attribute their discomfort to dehydration may feel bad because they drink too much water, Hyndman speculated. “Maybe they’ve got a headache or they’re feeling bad, and they’re thinking, ‘Oh, I’m dehydrated, I need to drink more,’ and they keep drinking more and more. water, and they feel worse and worse. “

If you drink at a faster rate than your kidneys can excrete, the electrolytes in your blood may become too diluted, and in milder cases, you may feel like you are “turned off.” In the most extreme case, drinking too much water in a short period of time can lead to a condition called hyponatremia or “water poisoning”. “It’s very scary and bad,” Hyndman said. If the sodium levels in the blood drop too low, it can cause swelling of the brain and neurological problems such as seizures, coma, or even death.

In 2007, a 28-year-old woman deceased of hyponatremia after drinking nearly seven liters of water for three hours while participating in a contest on the radio station “Hold your urine to win a Wii”, which challenged participants to drink water and then go as long as possible without urinating. In 2014, a 17-year-old high school football player in Georgia, deceased because of this condition after apparently drinking seven liters of water and seven liters of Gatorade.

The disease has become common enough among athletes that when someone collapses during a race, first responders are trained to consider hyponatremia, Topf said. Yet developing severe hyponatremia is rare for most healthy people.

How do I know if I am adequately hydrated?

Your body will tell you. The idea that being hydrated requires complex calculations and instant adjustments to avoid dire health consequences is just nonsense, experts said. AND one of the best things you can do is stop thinking about it.

In exchange, the best tips for staying hydratedAccording to Topf, it’s also the easiest: drink when you are thirsty. It’s as simple as that.

© The New York Times 2021