I wonder what the Beach Boys drink after a long gig under those hot stage lights. Seriously, though, water is a no brainer to stay ahead of thirst. But when you’re holding up more than a bass guitar, and your exercise is intense and lasts longer than one hour, a sports drink is really the way to go. 

Are you wondering what sports drink is best for you? Well, formulation is key. 

Isotonic drinks – meaning they have the same osmolarity (or concentration of dissolved particles) as your body’s own fluids – provide an immediate boost of the carbohydrate and fluid lost through sweat. An isotonic drink is the choice for endurance events, including middle and long distance running or team sports.

Hypotonic sports drinks, on the other hand, have fewer particles than body fluid. These beverages are suitable if you require fluid without the carbohydrate energy and fewer calories (if you’re a gymnast or jockey, for example).

Then there are the hypertonic drinks, which contain a higher concentration of carbohydrates (greater than 10 per cent). These will have a slow gastric-emptying rate, decreasing fluid absorption and making them more suitable for a post-workout drink to top-up muscle glycogen stores. Hypertonic drinks can also be taken during ultra-endurance exercise to meet energy demands but need to be taken in conjunction with isotonic drinks to replace fluids.

What to look for in a sports drink

The amount of carbs in a drink makes all the difference. For example, too few carbs will not benefit performance, while too many will slow fluid absorption. Therefore, the ideal concentration of carbs should be within a range of 4-8 per cent (4-8 g/100 ml), which ensures rapid fluid absorption and delivery of carbohydrates to fuel the working muscles. Most isotonic drinks sit within this range.
The type of carbohydrates also matters. Look out for a blend of sucrose and glucose, as these sugars complement each other: glucose gives instant energy and sucrose breaks down more slowly to give sustained energy. Avoid drinks containing high levels of fructose, as this cannot be absorbed as fast, and may also cause cramps and bloating.

As with carbohydrates, both the amount and type of electrolytes available is critical. A sports drink should contain approximately 23-69 mg/100mL (10-30 mmol/L) sodium. While there’s no recommended range for potassium, its addition to sports drinks is beneficial because potassium complements sodium with fluid absorption and also assists with muscle contraction during exercise.
The inclusion of magnesium in sports drinks has been the subject of much debate. Many scientists believe that a reduction of magnesium is implicated in muscle cramping. I think I just might dedicate a whole post to magnesium alone so stay tuned…

Palatability is important with sports drinks, too. Research shows that exercisers will drink more of a beverage with flavour compared to plain water, unless they don’t like the taste of the sports drink, in which case they won’t drink enough of it. Makes sense.
Kathleen Alleaume

Kathleen Alleaume is an accredited exercise physiologist and nutritionist and founder of The Right Balance