Sports Drinks

You’re entering hour four of your marathon. As you run towards an aid station your first impulse is to gulp down as much water as possible. Dehydration is a danger, right? Not so fast. All that water could be doing more harm than good by diluting your sodium levels. But what’s the alternative?

Many athletes choose sports drinks because they contain electrolytes that counteract dehydration and carbohydrates that provide energy. Carbohydrates also increase the amount of sodium that the body absorbs, which helps us retain more water.

Three types of sports drinks

Sports drinks can be divided into three categories: isotonic, hypotonic and hypertonic. Each one has a different percentage of carbs and electrolytes to meet the needs of different types of exercise.

Isotonic drinks provide a balance of electrolytes for rehydration and carbs for energy and are the most common sports drinks for athletes.

Hypotonic drinks have a low level of carbs. Their main purpose is speedy rehydration.

Hypertonic drinks contain a high level of carbs, which provide an energy boost rather than hydration. They are good for post-exercise recovery or for energy during ultra-distance events.

Prehydration benefits

Prehydrating about four hours before exercise allows the body to absorb the fluid and get rid of any excess. Drinking an isotonic beverage about 30 minutes before exercise can also be beneficial. The sodium allows the body to retain more fluid while stimulating thirst, and the carbs provide an energy boost.

Too much of a good thing

Hyperhydrating is not recommended because it dilutes sodium in the body and can lead to serious illness or death. In particular, drinking too much seems to be dangerous for slower marathon runners (four hours or longer) because they sweat less than faster runners but still consume a lot of water and hypotonic drinks.

A juice boost

An athlete may also choose to get a boost from drinking fruit or vegetable juice. Try mixing 2 cups (500 ml) unsweetened orange juice with the same amount of water and approximately 1/4 tsp (1 ml) salt.

If you are looking to shave minutes or seconds off your time, consider beetroot juice. Beetroot juice was found to boost performance in cyclists by 2.8 per cent when they drank 2 cups (500 ml) before a time trial. Beetroot juice also reduces resting blood pressure as well as the amount of oxygen needed to do exercise, including low intensity exercise such as walking.

Coconut water may also be a sports drink superstar, promoting whole-body rehydration. In a recent study sodium-enriched coconut water treated dehydration brought on due to exercise as effectively as a commercial sports drink.

Energy keeps you on track

The decision to drink during an event depends mainly on its duration. Former Olympic runner Nancy Tinari felt that she usually didn’t need to stop to take a drink. She says, “Since my main race distance was 10K, I rarely drank during a race. And the only time I drank during a workout was on an extremely hot day”.

When determining how much to drink during exercise, keep in mind that fluid and energy requirements differ dramatically based on the individual’s body type, fitness level and perspiration rate, as well as the type of activity and weather in question.

However, there are general guidelines you can follow. If the exercise lasts for an hour or longer, taking in carbs (1 to 2 oz/30 to 60 g per hour) will keep you going. Look for a drink with 6 to 8 per cent carbohydrates; more than 8 per cent is not recommended during exercise (unless it is an extreme event such as an ultra-endurance race), because a high level of carbs prevents the body from absorbing fluids.

When athletes have to put a lot of mental focus on a task, such as when playing golf, they can benefit from drinking caffeine before and during the activity. As well, one recent study has shown that cyclists who drink energy drinks with caffeine before exercise can improve their performance.

Not all drinks are created equal

When reaching for a sports drink, keep in mind that although they all contain carbs and electrolytes, the quantity and quality may not be the same.

One study compared two commercial sports drinks and found marked differences in the resulting performances. The drink that produced better treadmill times contained a glucose polymer—a complex carbohydrate that is absorbed and used by the body more efficiently than a simple sugar. The drink also contained fructose, dextrose, sodium, potassium, amino acids and vitamins B and C.

Post-exercise recovery

After a tough workout the body needs electrolytes to replace fluid, and carbs and protein to help the muscles resynthesise glycogen.

Recent research has revealed an alternative to commercial hypertonic sports drinks: low-fat chocolate milk. It supplies carbs, protein and amino acids, while replacing electrolytes (and has the added bonus of widespread appeal). One expert recommends drinking the equivalent of 50 per cent of kilojoules burned, about 20 to 30 minutes after exercise.

Listen to your body

It’s better to listen to your body and drink only when thirsty rather than follow a fixed drinking regimen. To assess your level of hydration you can use your urine output as a guide or compare your weight before and after exercise.

All of this experimentation should be done during training runs. “Never try anything new on race day”, urges Tinari.

Quick reference guide

Use this chart to determine which drinks to use to fuel your workout.