Will a sports drink help my performance? There is no single answer. Science-based recommendations for consuming fluid replacement beverages during exercise are determined by the type of sport, its intensity and duration, and the athlete's hydration status, nutritional status, and taste preferences.
Fluid replacement to prevent dehydration is an issue for both ice hockey players and cross country skiers. Even though ice hockey players train and compete on the ice, their clothing and protective gear trap the heat their bodies produce during exercise. Thus, ice hockey players actually train and compete in a hot environment. They must sweat to keep themselves cool.
Although the outdoor temperature during a cross country ski race may be very cold, skiers wear only the equivalent of a full body Lycra bathing suit. Why don't they get cold? Fast moving cross country skiers produce so much heat, a byproduct of energy production, that they must sweat, sometimes profusely, to keep their core body temperatures normal. Also, skiing at high altitude increases fluid loss via respiration. Less oxygen availability at high altitudes results in increased rates of respiration and additional fluid loss from breathing. Drinking fluids (water or a sports drink) to replace fluid loss helps ice hockey players and cross country skiers prevent dehydration and maintain high levels of performance throughout training sessions or competitions.
What do sports drinks contain compared to what an athlete's needs during exercise? That is one way to investigate whether consuming a sports drink may be beneficial. Commercial sports drinks typically contain water, carbohydrate, and electrolytes (sodium, chloride, and potassium.) Read on to see what each component of a sports drink can do.
Water: Adequate hydration is essential because all athletes, whether they train and compete indoors, outdoors, or in hot or cold weather, are at risk for dehydration. For most activities that last less than one hour, there is no significant difference in performance between consuming plain water or a carbohydrate-electrolyte beverage such as a sports drink. The 1996 ACSM guidelines for fluid replacement recommend that athletes drink fluids early and often during exercise. The goal is to drink enough fluid to replace all the water lost through sweating. When fluid balance is the primary goal, the best beverage is the one that the athlete likes to drink and will consume in sufficient volumes to replace fluid loss.
Carbohydrate: While maintaining hydration is a primary goal, fluids containing an appropriate carbohydrate concentration will not harm water delivery and may enhance endurance performance. Carbohydrate is the primary fuel for muscular work at high intensities. The longer the exercise continues past one hour, the more likely it is that blood glucose will be used to help supply energy for muscle contraction. Thus, carbohydrate is recommended for inclusion in the fluid replacement beverage for exercise lasting longer than one hour. ACSM guidelines recommend that the beverage be 4-8% carbohydrate and the delivery rate be 30-60 grams of carbohydrate per hour during endurance exercise lasting longer than one hour.Sodium: Sodium is the main electrolyte in sports drinks. Including sodium in fluid replacement beverages for activities lasting less than one hour is not necessary but the presence of sodium in the beverage may enhance palatability and maintain the athlete's drive for thirst. Thus, the athlete may drink more fluid and stay better hydrated during exercise when the beverage contains a small amount of sodium. For exercise lasting longer than 4-5 hours, drinking a beverage containing sodium helps offset sodium loss in sweat. In addition, the osmotic pressure exerted by sodium helps maintain blood volume, especially during prolonged endurance or ultra-endurance exercise.
What about ice hockey players?
What is the best beverage, water or a sports drink, for training and competing? Although a game of ice hockey lasts longer than one hour, each player's time in the game totals no more than 25-30 minutes. Since the active time is less than one hour, is water the best beverage? Maybe, but not necessarily. Several recent studies involving running, cycling, and tennis have shown that carbohydrate ingestion may benefit performance in intermittent, high intensity exercise lasting less than one hour. The exact mechanism for the performance benefit in these situations has not yet been determined.
Depending on what and when the players eat before a game or practice, carbohydrate consumption during exercise may help maintain blood glucose levels. Also, if a carbohydrate beverage encourages the athlete to drink enough fluid to minimize fluid loss, cooling will be promoted. Maintaining good hydration and normal body temperature during exercise can enhance the athlete's ability to generate power during intermittent, high intensity activities. What the athlete eats and drinks before the game and how well hydration is maintained during high intensity activities may determine whether water or a sports drink is a better choice for individual athletes.
What about cross-country skiers?What is the best beverage, water or a sports drink, for training and competing? In Olympic events, a 50 km cross country ski race for men is won within two hours. For women, the 30 km race is finished in less than one and a half hours. Because these events last longer than one hour, a carbohydrate/electrolyte sports drink is considered to be the best choice. However, each athlete needs to try various beverages to find the one that is most appealing and helpful in maintaining optimal hydration. High stress and high intensity exercise both slow the rate that fluid leaves the stomach on its way to the intestines and absorption into the bloodstream. Cooling will be slowed if fluid delivery to the blood is delayed. |
Also, stomach upset may occur when fluid stays in the stomach too long during exercise. Consuming water or a diluted sports beverage may be beneficial under high stress conditions. Testing the athlete's response to a variety of beverages during exercise is a critical part of the training process.
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