Pros and cons of isotonic drinks


In the summer heat, we quickly break out in a sweat. Why does an isotonic drink help to quickly compensate for fluid loss and when is this useful?

What are isotonic drinks?

Isotonic means “same pressure”. Isotonic drinks, also called electrolyte drinks, have the same pressure as our blood. This means that isotonic drinks contain the same concentration of minerals as our blood. The same mineral composition means that sports drinks can be absorbed more quickly by the body.

Hypotonic drinks

Hypertonic drinks are less suitable for athletes. Examples are ice tea or pure fruit juice. Hypertonic means that the concentration of dissolved particles is higher than in our blood – the body must therefore first dilute these drinks. How does it do this? It withdraws fluid from its own blood.

Hypotonic drinks

Hypotonic drinks have a lower number of dissolved particles per litre than blood has. This is the case with water or very thin juice spritzers, for example. The fluid can be absorbed quickly by the body but, during prolonged exercise, they don’t compensate for the loss of salt.

Good to know

The Swiss Society for Nutrition recommends drinking 1-2 litres a day in the form of unsweetened drinks. It’s important to supply the body with as much fluid as is lost during the day. People who do physical work or exercise should therefore drink more. The basic recommendation for sports activity today is about 400ml to 800ml of fluid per hour.

Disadvantages of isotonic drinks

Care should be taken with ready-mixed sports drinks in particular, as almost all of them have a very high acid content. Certain sports drinks are almost as acidic as stomach acid itself. Consuming these sports drinks in small sips throughout the day is particularly harmful to the teeth. It’s advisable to pay attention to the acid content when buying ready-mixed drinks. In addition, after drinking isotonic drinks, rinse your mouth with water and wait a while before brushing your teeth.

Advantages of isotonic drinks

Because isotonic drinks can have negative effects on dental health, they shouldn’t be used for every sporting activity – an isotonic drink isn't always needed.

When are isotonic drinks advisable?

For shorter and less intensive activities, tap water is usually sufficient. The minerals that are lost through sweating can be replenished with a balanced, wholesome diet.

However, for intensive sporting activities of more than 60 minutes, it’s worth drinking an isotonic drink to compensate for the loss of fluids and minerals. This can be purchased either as a concentrate in the form of powder, gel or tablets, or in diluted form. Alternatively, it’s easy to make an isotonic sports drink yourself. Not only is this easy on the wallet, it also has less sugar and additives.

Basic recipe: Isotonic drink

  • 2 parts water
  • 1 part juice (orange juice or apple juice), tea, or diluted cordial
  • 1/2 – 1 level teaspoon of salt (per litre)

Tip: Add a little lemon, ginger or mint for freshness.

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