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Health myths: how much fluid do we need to drink each day?


How much water is really healthy per day?
In all guides, on the Internet and in magazines, there is always a note that we should all drink a lot more. Drinking a lot promotes health is one of the main arguments. But how much should we really drink? And what determines when we drink? Is constant sipping a way out? Or should we just trust our thirst? This article gives a few answers from experts.

How much water does the human body need?

Through transpiration and metabolic processes, humans excrete about 2.5 liters of water every day, which must be balanced out again by eating liquid and drinking. An adult should drink about 1.5 liters a day. The remaining liquid is taken up with the food.

The fluid house plays an important role in the human body. Not least because the body consists of about 60 percent water, the brain even 80 percent. "Water is used in the body as a means of dissolving, transporting and eliminating," explains Susann-Cathérine Ruprecht, spokeswoman for the German Institute for Nutritional Research (DIfE) in Potsdam. If people drink too little, the fluid balance becomes unbalanced and certain processes, such as the supply of sodium, are disturbed in their processes. “Physical and mental performance is impaired from about three percent fluid loss,” reports Ruprecht.

Symptoms such as dry mouth and viscous saliva, loss of appetite, constipation, fatigue and exhaustion can occur. Confusion and mental deficits can also result.

Those who drink too little also excrete less urine than usual. In addition, this is colored darker. A healthy person should excrete about half a liter of urine a day. To determine whether the body is supplied with sufficient fluid, a skin fold on the arm can be pulled up slightly. If it stops briefly after releasing it, this is an indication of a lack of fluid. If there was an adequate supply of fluids, it would disappear immediately.

Thirst should determine drinking behavior

"When the body has lost half a percent of water, we feel thirsty," says Ruprecht. The thirst should not be ignored but in any case quenched. A glass of water is often enough. Antje Gahl from the German Nutrition Society (DGE) in Bonn points out that the most important thing is that “most drinks are low in energy”. Accordingly, they should contain little or no sugar. Mineral water is particularly suitable, but experts also recommend unsweetened teas and diluted fruit juices.

Does coffee draw fluid from the body?

Contrary to rumors to the contrary, drinking caffeinated coffee and tea is not unhealthy for healthy people as long as the caffeine is well tolerated. Neither coffee nor tea remove water from the body.

Sugared lemonades are less suitable than thirst quenchers because they are very high in calories. The same applies to fruit juices, which contain not only plenty of vitamins but also calories. Mixed with water, fruit juices are suitable as spritzers in moderation to quench your thirst. Restraint is advised when it comes to milk, because a glass of milk corresponds to a small meal. Alcoholic beverages are also unsuitable for quenching thirst. "A maximum of half a liter of beer for a male adult is just about acceptable," advises Gahl. About half of the amount applies to women.

Drink evenly throughout the day

The nutritionist recommends that you consume an even amount of fluid throughout the day. Anyone who drinks a lot at once cannot create a fluid depot in the body, because this eliminates the amount that they cannot consume.

If you take a long break from drinking or drink very little liquid, you can not immediately compensate for the lack of liquid with a large amount of water. It can take 24 hours before the body's fluid balance is balanced again. The human intestine is able to absorb about 500 to 800 milliliters of water per hour. If more liquid is added, it is simply excreted again. Accordingly, a glass of water per hour corresponds to the optimal amount of liquid.

Nevertheless, experts advise against too strict drinking rules. "Drinking is such an essential mechanism, you don't need any rules for it," says Uwe Knop, author of the book "Hunger & Lust". In his opinion, a healthy person "does not need a drinking alarm or the like, you can just drink according to your feelings".

Thirst disappears with age: the need for fluids remains approximately the same

"The feeling of thirst often subsides in old age," reports Gahl. "But the need is actually there." A lack of fluids is particularly dangerous for older people as well as for infants and young children. If in doubt, medical advice should be sought. People who are on a diet should also make sure they are hydrated properly. If the food is reduced, the body also lacks the water it contains.

Those who exercise a lot have an increased need for fluids. Nevertheless, the thirst feeling is often ignored, especially during physical exertion. “It is a well-known problem that people often drink too little in sports situations,” confirms Professor Daniel König from the Institute for Sports and Sports Science at the University of Freiburg. He also considers strict drinking control to be unnecessary for athletes. "The recommendation that athletes should constantly monitor the color of their urine is an exaggeration."

From a duration of one hour, physical exercise should be taken to ensure an adequate drinking amount, advises the sports doctor. When jogging for 20 minutes, there is still no danger of dehydration in healthy people.

No one takes a health risk if they drink too much. The experts agree on this. "The body can process ten liters a day without any problems," explains Gahl. Very rare deaths from watering are known to König only from extreme sports events: "The body then loses too much sodium, among other things, by drinking."

Encourage children to drink water

Children often forget to grab a glass of water when playing or at school. Children have a particularly high need for fluids. Because the younger a person is, the higher their water content in the body. The Children's Health Foundation therefore recommends fixed drinking rituals that can help to provide the children with sufficient and healthy fluids.

"Thanks to fixed rituals, neither the children nor the parents forget to drink enough," explains social worker Gritli Bertram from Hanover. "A glass of water right after getting up could be such a ritual, for example."

While children were previously prohibited from drinking during meals in order to counteract an early feeling of fullness, it is now common to give a glass of water to eat. “A glass of apple spritzer at every meal is generally well received by children. The parents often don't even have to encourage the children to drink, ”reports the social worker. (sb)

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