Do I really need a sports drink? Won't water do?

It depends on the intensity and duration of your workout. "Water is generally sufficient for shorter sessions, but for exercise lasting more than 60 minutes, an isotonic sports drink is recommended," says Wendy Martinson, registered dietician and sports nutritionist.

But Nick Morgan, head of sport science at Lucozade, believes sports drinks can be useful for shorter workouts, too: "If you've had a good high-carbohydrate meal in the three-four hours before your workout, you probably don't need a sports drink", he says. "But if you haven't eaten for ages - if, for example, you've just got up or have hit the gym straight after work, a sports drink will provide a little extra energy, helping you get more out of yourself and reducing your 'perception of effort.'"

Just for the record, a study in the Journal of Applied Physiology found that consuming an isotonic sports drink increased treadmill running time to exhaustion by 27% in recreational runners.

What should I look for in a sports drink?

According to Martin Gibala, an associate professor of kinesiology at McMaster University in Canada, there are two key ingredients in a good sports drink: "Carbohydrate, which provides fuel for working muscles, and sodium, which helps to maintain fluid balance."

But formulation is key. An isotonic drink (such as Lucozade Sport or Gatorade) contains a 6-8% carbohydrate solution, which is absorbed into the body more rapidly than water, as well as providing energy. A sports drink should also contain approximately 50mg of sodium per 100ml, along with smaller amounts of the other electrolytes, such as potassium and chloride, which are lost in sweat.

Morgan highlights another important consideration: palatability. "Studies show clearly that if you don't like the taste of a sports drink, you won't consume enough of it."


How much do I need to drink?

In 2007, the American College of Sports Medicine, an international authority on sport science, revised its guidelines on fluid intake during physical activity, no longer suggesting specific volumes per hour. "We now know that individual needs vary so much it is impossible to suggest a 'one size fits all' amount that will suit everyone", says Morgan. "Issues surrounding the risks of dehydration on one hand and hyponatraemia (water intoxication) on the other make this dangerous ground."

Should I drink before my workout, or just during?

It's important to start exercise well hydrated. Research suggests that the body cannot absorb ingested carbohydrate efficiently if the body is dehydrated, so even if you are guzzling sports drinks, they may be of limited benefit. The ACSM recommends drinking 5-7ml of fluid per kg of your body weight in the three-four hours before exercise. (So, if you weigh 60kg that means drinking 300-420ml.) If your urine is still dark after this, they suggest drinking a further 3-5ml/kg. Water will do just fine - but, says Martinson, consuming a sports drink helps to top up carbohydrate stores.