2 liters is not enough: According to experts, that’s how much water you need on hot days

Summer temperatures cause problems for many people. Drinking enough is extremely important. But how much water should you drink per day? And what are the best thirst quenchers in extreme heat?

Every child knows: Drinking a lot is important. Because we need water so that the metabolic processes function and our body stays healthy. Water transports the dissolved nutrients to the cells, our kidneys need water to flush waste products from the body and water helps regulate body temperature: our bodies produce sweat to cool the skin so that the body temperature does not rise too much.

What happens if we drink too little?

Even a small amount of fluid loss makes us less productive. We react with a headache, become tired and can no longer concentrate. If the deficiency is greater, circulatory problems, palpitations and dizziness can occur.

Anyone who doesn’t drink enough and becomes dehydrated for a long time can expect serious damage to their health, explains Professor Dr. Jan C. Galle, press spokesman for the German Society for Nephrology (DGfN). The blood thickens and this can lead to impaired consciousness, phases of confusion, a circulatory collapse and organ failure. In extreme cases, dehydration can be fatal. Older people and people with limited health are particularly at risk here.

What helps? When it’s hot in the middle of summer, we need significantly more fluids than usual. The need for fluids also increases during sport and physical exertion. But how much water should you drink on hot days?

How much you should drink in hot weather

Drink one and a half to two liters of water a day – that is a widespread general rule of thumb. This amount is recommended by the German Nutrition Society (DGE), the consumer advice center and numerous doctors.

Everywhere, however, the addition is: Drink more in hot weather. The DGE recommends drinking significantly more water when it’s hot, when you’re doing physically strenuous work or when doing sports: “Then 0.5 to 1 liter of water per hour may be necessary.” The consumer advice center advises: “Especially on hot days and during physical exertion, fluid intake should be increased – the fluid requirement can increase three to four times.”

Important here: There is no general minimum amount because every body works differently. This is also shown by a study by the Japanese National Institute of Biomedical Innovation. She measured the water consumption of more than 5,600 people and determined daily averages in a range between one and six liters per day. According to scientists, the amount of water required depends on gender, body size, weight, activity level, temperature, altitude, eating habits and a few additional factors.

Tip: Looking into the toilet bowl can help you see if you need more fluids. If the urine is light and clear, it is a sign that your body is well hydrated. An intense yellow tone shows that your body does not contain enough water.

Can you drink too much?

Purely theoretically, yes. However, healthy people do not have to be afraid of the phenomenon of water poisoning. The DGE gives the all-clear: “Drinking too much fluid does not harm the healthy organism. Healthy people simply excrete excess fluid through the kidneys.”

In a so-called water poisoning (overdrinking), the amount of sodium in the blood is so diluted that hyposalinization occurs. Extreme athletes and those with heart, kidney or liver disease should keep an eye on the amount they drink.

What drinks are best in the heat?

“Tap water, mineral water, unsweetened herbal and fruit teas as well as fruit juice and fruit juice spritzers are ideal refreshments on hot days,” is the consumer advice center’s recommendation. You should dilute juice spritzers significantly so as not to consume too much sugar. If you want, you can spice up mineral water with peppermint leaves or a slice of lemon. According to current scientific findings, coffee can be included in the fluid balance.

What is important is that not only fluid levels but also mineral levels must be kept in balance. Therefore, make sure you have sufficient electrolyte intake. “Tap water usually has enough dissolved mineral content to adequately cover the needs of a balanced diet,” explains the Federal Center for Health Education (BZgA).

Are isotonic drinks useful?

In isotonic drinks, the ratio of nutrients and fluid corresponds to that of blood. The result: the body can absorb the water from the drink very quickly. Öko-Test (issue 7/2023) had sports drinks tested in the laboratory. The result: Most sports drinks don’t contain enough sodium, which is important for muscle function but which we lose when we sweat.

The eco-testers make this judgment based on a recommendation from the German Nutrition Society (DGE) for sports drinks. Accordingly, 400 milligrams of sodium per liter is the minimum. Only four isotonic drinks in the test achieved this.

If you want a good isotonic sports refreshment, you can easily prepare it yourself: According to Öko-Test, you mix two parts water with one part juice, for example from apple or currant. For each liter of drink, you should add one gram of table salt to the liquid, which corresponds to 400 milligrams of sodium. If you don’t have a precision scale, you can alternatively measure four small knife tips or two large pinches of table salt.

Drinking in the heat – 7 tips

1. A lot of fluid is lost at night, so it’s best to start the day with a large glass of water.
2. Don’t (always) only drink when you’re thirsty.
3. On hot days, the drinks you consume should be neither too warm nor too cold.
4. Water-rich foods such as melon, cucumber, tomatoes or strawberries also provide the body with fluids.
5. If you exercise on hot days, you should drink even more. Read also: Sport in the heat: Prof. Ingo Froböse gives tips
6. If you sweat a lot, you should compensate for the fluid loss as soon as possible.
7. Don’t drink too much at once, but rather regularly and throughout the day.

If you have problems drinking enough, you can help with a few tricks:

• Place water within easy reach at your workplace or in your home.
• Refill the glass as soon as it is empty.
• Place notes around your home reminding you to drink.
• You can use a hydration app or an alarm clock to remind yourself.

Drink sustainably – this is how it works

• If you drink tap water, you save not only transport but also packaging and the hassle of lugging around boxes.
• If you buy drinks in packaging: preferably in the regional reusable bottle!
• The further drinks are transported, the worse their environmental impact is. Therefore: buy regionally bottled drinks.
• Reduce drinks from distant countries as much as possible. Coffee, many types of tea and exotic juices come from far away and are often produced under problematic conditions.
• We recommend environmentally friendly drinking bottles when on the go.

With material from dpa

Read more on Techzle\.com:

• Let the water run for a short time: necessary – or waste?

• 7 heat mistakes to avoid

• Sleeping in the heat: 11 common mistakes that rob you of sleep

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