DEBInet Nutrition Blog » Blog Archive Drink Enough: When Not to Trust Your Feeling of Thirst

Author: Dr. oec. Christina Bächle, editor: Dr. Bertil Kluthe
© Kluthe Foundation Nutrition and Health

Tuesday, April 19, 2022

What is the right amount to drink? This question cannot be answered in general. And it is that, depending on the state of health, the intake of too many or too few liquids can be harmful, warn experts from the German Society of Internal Medicine (DGIM) on the occasion of World Water Day this year, on March 22.

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More than two thirds of our body is made up of water, the blood even at 90 percent. Sufficient fluid intake is essential, ideally in the form of water, unsweetened tea, or a very diluted juice drink. It stimulates the metabolism, promotes digestion and can help reduce blood pressure. Sophisticated control mechanisms in the body ensure that the water content of the tissues and blood remains almost constant, even with changes in temperature and different levels of physical exertion. These include the amount of urine produced or the urge to urinate and the sensation of thirst.

What amount of drink is recommended? “In healthy people, there is nothing wrong with relying on the sensation of thirst in general”, explains Prof. Markus M. Lerch, Medical Director of the LMU Klinikum Munich and President of the DGIM. This generally results in recommended drinking amounts of one and a half to two liters per day. According to Lerch, wet foods like soups, fruits and vegetables can definitely be counted as drinking amounts. In addition to room temperature, the need for fluids also depends on body weight, age, diet, physical exertion and health status. In heat, dry cold air, high intake of table salt or protein, and acute illnesses such as fever, vomiting, or diarrhea, more should be drunk.

However, sometimes feeling thirsty is not a reliable indicator. This applies to old age. “In older people, the sensation of thirst decreases significantly”Lark warns. So you need to make sure you drink enough fluids and mindfully pour yourself a glass of water from time to time. The advice for people with diabetes is also to drink a little more. Because a slightly larger amount of drink promotes the excretion of sugar through the kidneys. Also, people taking diuretics should drink enough due to increased urine output.

Warning signs of dehydration include dark urine, stools may become harder, and symptoms of constipation may occur. A simple test is the skinfold test: To do this, lift a fold of skin with two fingers and then release it again. If there is a fluid deficit, the fold will remain for a short time. If, on the other hand, the body is sufficiently supplied with water, the wrinkle disappears again immediately. “Especially on hot days, the lack of fluids can worsen and become critical, which manifests itself in tachycardia, confusion and circulatory weakness until fainting”, explains Prof. Georg Ertl, internist, cardiologist and general secretary of the DGIM. The kidneys also suffer from lack of fluids (dehydration), and even acute kidney failure can occur.

Does that mean the more you drink, the healthier you are? Ertl expressly warns against this reverse conclusion. Because with certain diseases, drinking large amounts can even be harmful. “This is the case, for example, in patients with advanced heart failure, in whom too much fluid puts excessive pressure on the heart,” enumerate Ertl. If you have kidney disease, you may need to drink less.

In addition, the body’s fluid balance is closely linked to its mineral balance. Drinking too much therefore risks electrolyte depletion, especially if you eat little or nothing at the same time. This danger exists, for example, with fasting cures or an eating disorder. “Even athletes or physically working people who lose a lot of electrolytes through sweat can throw their mineral balance out of balance by drinking large amounts”Ertl continues. He recommends quenching thirst with a juice soda or non-alcoholic beer. In this way, the loss of electrolytes can be compensated for at the same time.

written by dr. oec. trophic Christina Bächle on April 19, 2022 at 09:10



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