Sports Drinks: Using Electrolytes and Carbohydrates Properly

These three terms describe the concentration of dissolved particles in the drink compared with blood plasma, known as osmolality. It influences how quickly the fluid is absorbed from the stomach into the body.

Isotonic drinks are considered a good compromise between fast fluid absorption and energy supply and are therefore most often promoted for endurance sport. Hypotonic versions contain fewer dissolved particles and are absorbed slightly faster, but also supply less energy. Hypertonic drinks are used more after training, when quickly refilling energy stores is the priority and fluid intake takes place over the following hours.

For short training sessions of under about an hour at moderate intensity, water is enough in most cases, especially if a normal meal follows. Sports drinks become relevant mainly in the following situations.

• Endurance exertion of about 60 to 90 minutes or more, for example running, cycling or high-intensity team sport.
• Training in heat or with a high sweat rate, when electrolyte losses are correspondingly greater.
• Multiple bouts on the same day, for example at tournaments, when there is little time for normal meals between sessions.

For pure strength training in the gym, a sports drink is usually not necessary; the focus here is more on protein supply around training. In shorter but very intense sessions such as high-intensity interval training, a small amount of carbohydrate during exertion can still be helpful, but a full sports drink is generally not necessary for that.

With a little practice, an isotonic drink can also be made yourself, for example from water, a small amount of fruit or grape juice and a pinch of salt. Ready-made sports drinks have the advantage of a consistent, precisely declared composition, while a homemade version can be adjusted flexibly and is usually easier to keep lower in sugar.

A dietary supplement or sports drink should always be understood as an addition, not a replacement for an overall balanced diet with sufficient fluid outside training as well.

For endurance exertion lasting about an hour or more, the combination of carbohydrates and sodium in drinks is well studied and shows advantages over plain water in studies for fluid absorption and performance. For shorter or low-intensity sessions, the benefit hardly matters, and the additional sugar intake without a relevant advantage tends to outweigh it.

For individual additives, such as certain amino acids or plant extracts in some sports drinks, the evidence is considerably weaker and often cannot be clearly translated into better performance. A differentiated look at the actual training situation therefore makes more sense than a blanket recommendation for or against sports drinks.

Individual sweat loss also differs greatly from person to person and depends on temperature, humidity, training status and genetic predisposition. Fixed drinking amounts that apply to everyone therefore cannot be derived from research; it is more helpful to use thirst, body weight before and after training and the colour of your urine as rough guides.

Can I lose weight with sports drinks?

Sports drinks generally contain carbohydrates and therefore calories, and they are not a weight-loss product. If your goal is weight reduction and your sessions are short, water is usually the better choice, see also protein for weight loss.

How much should I drink during training?

This depends heavily on sweat rate, temperature and duration of exertion, and no blanket amount can be reliably given. As a rough guide, drink regularly in small sips instead of large amounts at once.

Are sports drinks suitable for children or older people?

In principle possible during intense, long-lasting exertion, but for children, older people or those with pre-existing conditions such as high blood pressure, medical advice is advisable because of the salt and sugar content.

Are there low-sugar sports drinks?

Yes, some products use sweeteners instead of sugar and thus mainly supply electrolytes with fewer calories. For very long endurance exertion, a certain amount of carbohydrate still makes sense to ensure energy supply during exertion.

What is the difference from a protein shake?

A sports drink mainly supplies fluid, carbohydrates and electrolytes for use during exertion, while a protein shake serves protein supply after training for recovery, see protein timing.

Can too much sports drink be harmful?

In usual amounts, serious side effects are rare. Very large amounts of sugar or electrolytes at once can, however, burden the stomach or in rare cases lead to loose stools, which is why steady intake over the training period is recommended.

Is water with a pinch of salt enough as a substitute?

For many recreational athletes, a simple homemade version of water, a little juice and a pinch of salt is a practical and usually sufficient alternative to a ready-made product, as long as training duration and intensity stay moderate.