Successfully competing in endurance sports such as running, cycling, cross-country skiing, and swimming requires close attention to fueling the athlete's body with fluids and foods consistently. Steady, but not necessarily slow, wins the race.

Fluids: Staying Properly Hydrated

Endurance athletes, especially those who train in hot and humid weather conditions, constantly risk dehydration. The risk becomes greater the longer an athlete is working, or when athletes train or compete more than once in a day.

• If exercisers lose too much fluid in sweat without replacing what they've lost in both fluids and electrolytes (like sodium and potassium), they risk becoming dehydrated. Endurance athletes can use sports drinks, like Gatorade®, to help ward off dehydration and muscle cramps by replacing fluid or electrolytes.
• Dehydration can diminish energy and impair performance. Even a 2-percent loss of body weight through sweat (i.e., 3 pounds for a 150-pound runner)^1,2 can put athletes at a disadvantage. When the difference between top finishers in an endurance event is only a few seconds or less, athletes can't afford to lose time due to dehydration.

The Right Way to Hydrate

Because endurance events last longer than most sports, endurance athletes also run a higher risk of overhydrating, so hydration plans for these athletes should be considered carefully.

• Remember fluids throughout the day. It's important for endurance athletes to come to workouts and competitions hydrated. To do this, athletes can start out the day by grabbing a sports drink, then using fountains, coolers, and other beverages as triggers for drinking throughout the day.
• Hydrate 2 to 3 hours before training and competitions. Aim for at least 16 ounces (2 cups) of fluid at this time and an additional 8 ounces (1 cup) 10 to 20 minutes prior to getting on the field.
• Drink to replace sweat; don't overdrink. Endurance athletes, especially inexperienced marathoners who tend to run slowly and stop for more fluid breaks, risk overhydrating, which can lead to a dangerous condition called "hyponatremia". Hyponatremia occurs when an athlete takes in too much fluid and the sodium level in blood drops too low. All endurance athletes should know how much fluid their body requires and use their sweat rate as a guide (see sweat rate chart below).

Foods: Before, During, and After Fuel

For energy to get through a workout or event, athletes should fuel their bodies 2 to 3 hours before training and competition. If solid food before an endurance event doesn't sit well in an athlete's stomach, they can try eating a small meal, 4 to 5 hours before the event. Then, drink a small liquid snack or meal a couple hours before the competition for an extra boost.

Pre-workout fueling tips:

• Consume a pre-competition team meal, with high-energy foods like breads, cereals, pasta, rice, fruits and vegetables — as well as lean sources of protein. Athletes should fill 2/3 of their plates with high- carbohydrate options.
• Endurance athletes should also pay close attention to the meal the night before the event and eat what works for them. This is a good time to load up on easy-to-digest carbohydrate sources like pasta, rice, bread, potatoes, fruits, and juices with the meal.
• Athletes should make sure to replace the sodium lost in sweat — especially if they're heavy crampers. Athletes can do this by regularly salting their food and eating some salty snacks like pretzels, crackers and soups. In general, endurance athletes should not adhere to a low-sodium diet.
• Experiment with what works for fueling during competitions (bars, gels, goo, etc.).
• Boost energy and glycogen stores by consuming high-carbohydrate foods and fluids in the "30 minute window" after exercise.

Carbohydrates and Endurance

Carbohydrate is the body's "energy powerhouse" that fuels muscles for training and competitions and is essential to building glycogen stores and providing the long-haul energy that is so important in endurance events.

Sample high-carbohydrate training diet:

1 Gisolfi, C.V. and D.R. Lamb. Perspectives in Exercise Science and Sports Medicine: Fluid Homeostasis During Exercise, Chapt 1 pp. 1-38, 1990.

2 Gopinathan, P.M. et al. Arch Environ Health, 43:15-17, 1998.

* Snickers is a registered trademark of Mars, Incorporated.

Foods & Fluids Series: Volume I, ENDURANCE SPORTS is one in a series of six sports science articles written by Susan Kundrat, M.S., R.D., L.D., an expert in sports nutrition. Any of these articles can be reproduced for educational purposes to distribute to athletes, students, parents or to post in the athletic training room, locker room, or weight room.

CONTACT: FOR MORE INFORMATION ON THE GATORADE SPORTS SCIENCE INSTITUTE (GSSI) LOG ON TO: www.gssiweb.com or call 1-800-616-GSSI (4774).