What are Sport Drinks?
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Sport drinks were pioneered in the 1960s when a scientist at the University of Florida (home of the Gators) developed a product designed to provide fluid, energy, and electrolytes to athletes. The product became known as Gatorade, and a multimillion-dollar industry was born. Sport drinks provide fluid, energy and electrolytes and possibly other nutrients such as protein, amino acids, calcium, magnesium, B-complex vitamins and antioxidants. |
What is the composition of sport drinks?
The energy in sport drinks is provided largely in the form of carbohydrates such as glucose, sucrose, fructose, corn syrup, maltodextrins, and glucose polymers. Maltodextrins and glucose polymers are mostly cornstarch that is partially broken down. Glucose and fructose are monosaccharides, whereas corn syrup is derived from cornstarch, which has been partially broken down to short, branching chains of glucose. Maltodextrin is just a few glucose molecules linked together with a branching point. Glucose polymers may just be short chains of glucose. Carbohydrates usually make up about 6 to 8 percent of the sport drink. Recently protein and amino acids have been formulated into sports drinks with research suggesting better hydration, performance and recovery.
What is the relationship between sport drinks and sweat?
Sweat is a combination of mostly water and electrolytes. Sweat is needed to help remove the excessive heat generated from the body during exercise. One liter of sweat allows for the removal of 580 calories of heat from the body. So, if an activity such as running for two hours generates about 900 Cal of heat, then theoretically about 1.5 L of sweat may have been lost. The primary electrolytes lost from the body in sweat are sodium and chloride. However, their concentration in sweat is lower than in the plasma of the blood. Thus, sweat is dilute compared to blood. Even when sweating profusely the sodium and chloride content of the sweat may be only about one-half of the concentration of human blood plasma.
How does the carbohydrate in sport drink help sustain performance?
One of the principal factors involved in the onset of exhaustion or fatigue is a depletion of muscle glycogen stores. The carbohydrate in sport drinks becomes an available source of glucose to working muscle. It was once thought that the carbohydrate in a sport drink might slow the rate of glycogen breakdown and thus prolong endurance exercise. However, research has shown that the carbohydrate in a sport drink actually becomes an increasingly more important carbohydrate source for working muscle as glycogen stores wane. This contribution seems to be significant enough to push back fatigue by minutes or more. This could be the difference in finishing strong during a marathon or fatiguing in the last couple miles.
Who would benefit from a sport drink?
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For a well-nourished and hydrated weight-training athlete, there is probably not a need for a sport drink unless he or she is training for several hours and sweating profusely. The need for sport drinks for endurance athletes largely depends on the duration of exercise and the environmental conditions. Generally, for single shorter events such as 5K runs and half-hour aerobic sessions there isn’t a need. However, as an event or training session becomes longer, the need increases. For bouts lasting an hour or thereabouts, water replacement is certainly necessary and performance can be enhanced by a sport drink. |
Even athletes competing in intermittent effort yet longer duration sports such as soccer, ice hockey, and football can benefit from a sport drink. These sports are powered by muscle glycogen and a sport drink can improve performance in repeated sprinting efforts. Plus for sports such as ice hockey and football uniforms and gear can increase sweating and thus the need for fluid to maintain optimal hydration.
Can fortified water/fitness water help performance?
Over the past few years numerous enriched waters or fitness waters such as Propel™ and Option™. These beverages tend to be low calorie (e.g. 10 calories per 8-10 ounces) and include electrolytes with or without calcium, magnesium and B-vitamins. While these beverages are not advantageous for more strenuous and/or prolonged athletic efforts they are good options for maintaining optimal hydration especially in the heat (e.g. walking or a half hour or so on the elliptical or weight lifting.
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