What makes the optimum sports drink?

The fluid-replacement needs of exercisers and athletes have been scrutinized by exercise scientists and medical researchers at the Gatorade Sports Science Institute (GSSI) for several decades.

According to GSSI Director Bob Murray, scientists first began studying fluid loss in the mid-1960s when University of Florida football players started having problems related to two-a-day workouts in extreme heat and humidity.

In an effort to remedy the problem, University of Florida researchers experimented by adding carbohydrates and electrolytes to water to find the right concentration to aid hydration and prevent cramping.

After much experimentation, the formula worked, and the first sports drink was ready to hit the market. The new fluid replacement drink became known as "Gatorade," in honor of the University of Florida's football team, appropriately nicknamed the Gators.

Over the years, Murray and his colleagues learned exercisers and athletes need a small percentage of carbohydrate solution and trace amounts of electrolytes, in the form of sodium and potassium, to keep the body hydrated and functioning efficiently.

According to GSSI researchers, there are four major components that make up the optimal sports drink.

1. Carbohydrate content

The amount and percentage of carbohydrate solution makes a difference in terms of influencing the physiological response to fluid loss. For example, too little carbohydrate content won't benefit performance, while too much slows fluid absorption.

GSSI researchers have shown a 6 percent solution, or 6 grams of carbohydrate per 100 ml of beverage, strikes the optimal balance in taste, rapid fluid absorption and delivery of carbohydrate energy to fuel the working muscles.

2. Carbohydrate type

The optimal sports drink contains a blend of sucrose and glucose-fructose syrups to take advantage of the way the body absorbs fluid. Sports drinks containing only fructose or high levels of fructose should be avoided, because it cannot be absorbed as fast as other carbohydrates.

It takes 20 to 30 minutes for the body to convert these carbohydrates into energy for the muscles. High levels of fructose may also cause gastric distress.

3. Taste

Flavor makes a difference. The GSSI has conducted research on taste preferences during exercise when people are hot and sweaty. Research shows exercisers and athletes will drink more of a beverage with flavor.

The optimal sports drink will incorporate this knowledge to assure that its product tastes best when it is needed most.

4. Sodium and potassium

As with carbohydrates, both the amount and type of electrolyte are key factors in a scientifically based sports drink. Electrolytes, like sodium, help determine how much fluid is consumed and how much of that fluid remains in the body for proper hydration. Potassium helps prevent muscles from cramping.

Conversely, there are two ingredients you do not want in a sports drink because they don't supply energy or assist with hydration during an exhaustive workout or intense competition. Those ingredients are caffeine and carbonation.

Caffeine is a drug, not a nutrient. It does not provide energy for the working muscles like carbohydrates, or help with hydration. In addition, caffeine has a diuretic effect that can limit rehydration by increasing urine production.

As for carbonation: in a sports drink, bubbles get in the way of drinking because you can't drink the beverage very fast or in large volumes. In addition, carbonation can add to gastric distress.

The beverage comparison chart below was created by GSSI researchers.

Sport drink comparison chart

This beverage comparison chart by the Gatorade Sports Science Institute compares ingredients of six beverages. The actual study compares 20 drinks, but for the purposes of this article, only six beverages are compared, all based on 8 fluid ounces.

(Product: %carbs, grams, calories, sodium, potassium, carbonation, caffeine)

Accelerade: 7, 17, 93, 127ml, 43ml, No, No

Cytomax: 4, 10, 48, 50ml, 55ml, No, Yes

Gatorade: 6, 14, 50, 110ml, 30ml, No, No

Orange juice: 11, 26, 112, 3ml, 496ml, No, No

Regular cola: 12, 28, 98, 33ml, 0ml, Yes, Yes

Sun Lemonade: 14, 32, 120, 0ml, 0ml, No, No

For their complete comparison of 20 drinks and to access more information, see www.gatorade.com.

John Bobalik is an exercise physiologist and coordinator of Purdue University Calumet's Fitness Center. He can be reached by e-mail at hero@calumet.purdue.edu.

To see the entire chart as well as access more information on research articles and the latest findings on sports drinks, check out the Gatorade Web site at www.gatorade.com. For more information on the latest in proper sports nutrition and hydration, visit www.hydrationworkshops.com.

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