How much should I really drink in the summer?

With carbon dioxide or without, only in thirst or before...? Many myths revolve around correct drinking behavior. What is true - and what is not?

1. “In the summer it should be three liters of fluid per day.”

This advice is repeated like a mantra, but it's not always true, says the professor of prevention and kinesiology.

"If I drive to work in an air-conditioned car, in order to spend eight hours in an air-conditioned workplace, I definitely don't need three liters of liquid. Even on hot days, not much evaporates." This means: The amount of drink required depends not only on outside temperatures, but also on other aspects - how much do I sweat, how much do I move? A marathon runner will likely need more than three liters, an office worker might get by with one and a half liters.

However, it should not be less than this minimum daily, because the body needs fluid for all metabolic processes. In addition, you should absorb about 900 milliliters of water through wet foods such as cucumber or watermelon. Surprise: Even bananas are 75 percent water, lean beef is 72 percent and rye bread is still 40 percent.

2. “If you sweat a lot, you need a drink with magnesium, otherwise there are threatening cramps”

“Basically, the tendency to start cramping could indicate drainage,” experts say. Delivering fluid is a good idea for sweating. Whether with or without magnesium, the sports doctor considers this irrelevant. Because #magnesium deficiency is not an acute threatening situation. It is very important to provide salt with threatened dehydration over liquid containing sodium, otherwise the mineral balance in the blood is disturbed and thus circulatory problems can occur. By the way, drinks containing magnesium do not act suddenly against spasms, and the effect begins only in the long term.

3. “It is enough to drink only after feeling thirsty.”

“I would say on an average day where there is not much stress: yes,” the nutritionist confirms, “however, provided that someone has a good sense of how they are feeling and recognizes the early signs.” However, if there are special athletic or intellectual challenges, the expert advises regular drinking before the onset of thirst. This avoids the onset of water deficiency which can affect physical and mental performance to a great extent.

“Studies have shown that a fluid deficit of 0.5 percent of body weight actually slows down the speed of information processing in the brain,” he said. On a normal work day, it is best to drink a cup of water every one and a half to two hours. Depending on the amount of sweat, a cup may contain anywhere from 150 to 300 milliliters of liquid depending on the sweat.

4. “CO2 is unhealthy”

You can't say it like that. "The carbon dioxide molecule, which creates carbon dioxide in connection with water, occurs naturally in the body and is involved in many processes. It does not harm us," explains the nutritionist. “However, water is still friendlier to the stomach and can be drunk faster.” In particularly sensitive people, carbon dioxide can lead to stomach pain, for example when cycling or sitting in a hunched position. In the worst

cases, a quickly drunk amount of fizz leads to vomiting.

5. “If you get hot, you shouldn't drink cold.”

You hear it over and over, but an icy drink is often just too tempting. Nutritionists find this in principle. Limitations: “The body does not have to warm up lukewarm drinks, we can absorb a greater amount of it and it generally has a better cooling effect for the body.” Nutritionists also warn of potential problems for a sensitive stomach. “The gastric mucosa reacts to strong cold stimulation with a small shock.” Because the stomach is supplied with a variety of nerves, nausea or pain can occur.

6. “Water can't get bad”

incorrect. Both tap water and water from a bottle can be filled with germs and cause intestinal problems. “The problem with tap water: It's been checked in the water business, but not on durability at home. For example, the perlator on a tap is a perfect breeding ground for mold spores and bacteria that can then go into the #water,” the nutritionist explains. When drinking from a bottle, germs also get in. The sun increases potential pathogens quickly.

7. “The color of urine reveals whether you are drinking enough.”

“In fact, urinary color in healthy people is a useful indicator of adequate hydration,” emphasizes the nutritionist. However, some foods, such as beets, can fake the impression of color. “With a high dose of vitamin C, urine appears strikingly light yellow,” says the doctor.

8. “You can't drink too much.”

It sounds crazy, but an excessive amount of drinking can actually lead to “water intoxication.” “The excess fluid in the body is usually regulated very quickly through urine production and excretion,” says the nutritionist. In extreme situations such as triathlons, it has happened that athletes consume huge amounts of sodium drinks within a few hours. “Then the blood becomes thin, electrolyte balance can be thrown off and hyponatremia occurs. In the worst cases, organ failure threatens.” There have been deaths, for example in the United States after a water drinking contest or more recently in 2015 at an Ironman event.

9. “Coffee deprives the body of water”

This has been the common doctrine for a long time, but now one knows: “Those who drink coffee regularly the original dehydration effect no longer occurs. Therefore, moderate amounts, about three to four cups a day, can be added to the drinking balance sheet.”