When it comes to fluid management and rehydration during training or exercise, should you use a traditional “isotonic” sports drink or a more recent development called a “hypotonic” sports drink? 

Firstly, the term isotonic means that the dissolved Electrolytes and sugars in an isotonic drink at the same concentration as our blood. 

A hypotonic drink, on the other hand, is much more dilute than blood, meaning there is a lot more water in a hypotonic drink for the same amount of electrolytes compared to an isotonic drink.  

So what exactly are the differences, and which one is best for me? 

Most isotonic drinks, which are heavily marketed today, have around the same amount of mineral electrolytes (and often much less) than modern hypotonic drinks; however, isotonic drinks are much higher in dissolved sugars and carbohydrates. It is the high amounts of these dissolved sugars etc, and not the mineral electrolytes, which push up their concentration to make them isotonic. Isotonic drinks are often sold as “energy” drinks rather than electrolyte replacements because of their high sugar content.   

The question then comes down to which do I need more, an energy drink high in sugar or an electrolyte drink high in water.    

In sports exceeding 90 minutes, a high sugar energy drink might be a good option. Discuss this with your nutritionist.  

For sports less than 90 minutes, your body’s supply of glycogen should maintain your blood glucose for the duration, and your focus should remain on staying hydrated as performance will decline as you become dehydrated. This is one reason why hypotonic drinks have become so popular in recent years.  

Hypotonic sports drinks

Best for Rapid rehydration

When to use: Pre-hydration, on shorter workouts, on long rides, in hot weather; when you need a drink to rehydrate quickly & effectively.

Isotonic sports drinks 

Best for Carbohydrate release

When to use: Duration over 90 minutes; when you need carbohydrates more than hydration during endurance exercise.

NB:  PowerAmp Sport’s Rapid Hydration Electrolyte Powder provides 2-3 times faster rehydration than water.