Things you need to know about sports drinks

Sports drinks are very common in the world of sports. Everybody knows that sports drink can prolong intense activity, since it provides the body with the fast to use energy it needs. What remains unclear, are the questions of which sports drink and how much.

What is the optimal amount of carbohydrates?

Carbohydrates are the main source of energy for combat sports athletes, and the more available they are, the more you can make out of the training. The amount of carbohydrates you need during training depends on the training that you’re about to have and your body size. The general guidelines recommend 0.7g carbohydrates per hour of training for each kg of body weight.

Practically this means that if you take a standard sports drink of 7% carbohydrates (7g of sugar per 100ml), you need to multiply your body weight by 10 to receive the amount in milliliter you need for every hour of training. For example, a fighter of 70kg will need about one liter of sports drink for 1.5h of training (70 x 10 x 1.5 = 1050ml).

This number calculates only the recommended carbohydrates intake, which is not necessarily the same as the recommended water intake. In case you need more water during training, you can take a water bottle with you in addition to the sports drink, or dilute the sports drink. Manufacturers might tell you that diluting sports drinks with water is not good, as it compromises the optimal content and taste, but this advice is biased. They are worried that diluting drinks will damage their sales.

What is “isotonic drink”?

When a sports drink contains too many carbohydrates, its absorption slows down. It means that your body doesn’t hydrate as fast as you’d expect, and it can also lead to gastrointestinal problems. Therefore the best sports drink are not the ones with the highest percentage of carbohydrates, but the right percentage.

Often you see the label “Isotonic” on sports drink. Isotonic means that the concentration of dissolved substances (carbohydrates and salts) in the sports drink is the same as the concentration of dissolved substances in the blood. Which means that it contains the maximal amounts of energy without compromising absorption speed.

Normally, sports drinks of 6-8% carbohydrates are considered isotonic, however, research shows that this guideline may not be true for all brands. Don’t trust the “isotonic” label on your sports drink. If you experience an upset stomach or a dry mouth during training after drinking a sports drink, diluting it can solve the problem. It might be that the concentration of dissolved substances is a little too high to be isotonic.

Don’t drink too much!

While doing intense sport sports drink can be advised, outside of sports they are just as bad as soft drinks. Sports drinks can improve performance but should be handled with care. Most sports drinks are acidic. Constantly exposing your teeth to this acidic environment puts them at risk of erosion. Lastly, a typical bottle of sports drink contains about 140 calories. If you watch your intake, this is certainly something to take into account.

For the geeks among us

To be isotonic a drink should have an osmolality between 270-300mmol/kg. In the table below you can see the osmolality of commercially available sports drinks. As you may notice not all ‘isotonic’ sports drinks are truly isotonic, unfortunately, those numbers are not always displayed on the bottle.

Source:
Mettler, S., Rusch, C., Colombani, P.C. (2016). Osmolality and pH of sport and other drinks available in Switzerland. Schweizerische Zeitschrift fur Sportmedizin und Sporttraumatologie.

Read more:

• Original article: Osmolality and pH of sport and other drinks available in Switzerland.
• Sportdranken in JudoContact okt-nov-dec 2012
• Blog post: How much and what should I drink?