Fluids and Hydration

   How important are fluids?
 

Fluid replacement is probably the most important nutritional concern for athletes. Approximately 60% of your body weight is water. As you exercise, fluid is lost through your skin as sweat and through your lungs when you breathe. If this fluid is not replaced at regular intervals during exercise, you can become dehydrated.

When you are dehydrated, you have a smaller volume of blood circulating through your body. Consequently, the amount of blood your heart pumps with each beat decreases and your exercising muscles do not receive enough oxygen from your blood. Soon exhaustion sets in and your athletic performance suffers.

If you have lost as little as 2% of your body weight due to dehydration, it can adversely affect your athletic performance. For example, if you are a 150-pound athlete and you lose 3 pounds during a workout, your performance will start to suffer unless you replace the fluid you have lost. Proper fluid replacement is the key to preventing dehydration and reducing the risk of heat injury during training and competition.
 
 
How can I prevent dehydration?
 

The best way to prevent dehydration is to maintain body fluid levels by drinking plenty of fluids before, during, and after a workout or race. Often athletes are not aware that they are losing body fluid or that their performance is being impacted by dehydration.

If you are not sure how much fluid to drink, you can monitor your hydration using one of these methods.

Weight:Weigh yourself before practice and again after practice. For every pound you lose during the workout you will need to drink 2 cups of fluid to rehydrate your body.

Urine color:Check the color of your urine. If it is a dark gold color like apple juice, you are dehydrated. If you are well hydrated, the color of your urine will look like pale lemonade.
Thirst is not an accurate indicator of how much fluid you have lost. If you wait until you are thirsty to replenish body fluids, then you are already dehydrated. Most people do not become thirsty until they have lost more than 2% of their body weight. And if you only drink enough to quench your thirst, you may still be dehydrated.

Keep a water bottle available when working out and drink as often as you want, ideally every 15 to 30 minutes. High school and junior high school athletes can bring a water bottle to school and drink between classes and during breaks so they show up at workouts hydrated.

What about sport drinks?
 

Researchers have found that sports drinks containing between 6% and 8% carbohydrate (sugars) are absorbed into the body as rapidly as water and can provide energy to working muscles that water cannot. This extra energy can delay fatigue and possibly improve performance, particularly if the sport lasts longer than 1 hour. If you drink a sports drink, you can maintain your blood sugar level even when the sugar stored in your muscles (glycogen) is running low. This allows your body to continue to produce energy at a high rate.

Drinks containing less than 5% carbohydrate do not provide enough energy to improve your performance. So, athletes who dilute sports drink are most likely not getting enough energy from their drink to maintain a good blood sugar level. Drinking beverages that exceed a 10% carbohydrate level (most soda pop and some fruit juices) often have negative side effects such as abdominal cramps, nausea, and diarrhea and can hurt your performance.

What does the sodium in sports drinks do?
Sodium is an electrolyte needed to help maintain proper fluid balance in your body. Sodium helps your body absorb and retain more water. Researchers have found that the fluid from an 8-ounce serving of a sports drink with 6% carbohydrates (sugars) and about 110 mg of sodium absorbs into your body faster than plain water.

Some parents, coaches, and athletes are concerned that sports drinks may contain too much sodium. However, most sports drinks are actually low in sodium. An 8-ounce serving of Gatorade has a sodium content similar to a cup of 2% milk. Most Americans do get too much sodium, but usually from eating convenience-type foods, not from sports drinks.

What are guidelines for fluid replacement?
Drink a sports drink containing 6% to 8% carbohydrate to help give you more energy during intense training and long workouts. To figure out the percentage of carbohydrate in your drink use the following formula:
grams of carbohydrate/serving X 100 = % of carbohydrate in drink ml of drink/serving

For example, 240 ml (a 1 cup serving) of a drink with 24 grams of carbohydrate per serving would have a 10% carbohydrate concentration. Almost all drinks have the grams of carbohydrate per serving and the volume in ml somewhere on the container.

Drink a beverage that contains a small amount of sodium and other electrolytes (like potassium and chloride).

Find a beverage that tastes good; something cold and sweet is easier to drink.

Drink 10 to 16 ounces of cold fluid about 15 to 30 minutes before workouts. Drinking a sports drink with a 6% to 8% carbohydrate level is useful to help build up energy stores in your muscles, particularly if the workout will last longer than 1 hour.

Drink 4 to 8 ounces of cold fluid during exercise at 10 to 15 minute intervals.

Start drinking early in your workout because you will not feel thirsty until you have already lost 2% of your body weight; by that time your performance may have begun to decline.

Avoid carbonated drinks, which can cause gastrointestinal distress and may decrease the the fluid volume.

Avoid beverages containing caffeine and alcohol due to their diuretic effect.

Practice drinking fluids while you train. If you have never used a sports drink don't start during a meet or on race day. Use a trial-and-error approach until you find the drink that works for you.

 

Precompetition Meals

What's the purpose of the precompetition meal?

The precompetition meal serves two purposes: to keep you from feeling hungry before and during the event and to maintain the levels of sugar in your blood for your exercising muscles to use during training and competition.

Many young athletes often skip meals before they train or workout, especially if the workout is in the early morning. Skipping meals or not eating before an early morning workout lowers the stored energy in your body and can impair your performance, particularly if your workout involves endurance training that lasts 30 minutes or longer.

When should I eat my precompetition meal?
Your stomach should not be full during your event. In general, it takes 1 to 4 hours for your stomach to digest a meal and empty it into your intestines. If you are nervous the digestive process may take even longer. Food that remains in your stomach during competition may cause indigestion, nausea, and vomiting. If you eat your pre- event meal 1 to 3 hours before the start of your competition, your stomach will be almost empty during the event.

What's a good precompetition meal?
Your pre-event meal should include foods that are high in carbohydrates like breads, pasta, fruits, or vegetables. These foods are removed rapidly from your stomach and intestines. Carbohydrates also help build up the stored energy in your body for use later during your event.

To avoid indigestion or nausea, the closer you are to your event the less you should eat. You can have a liquid meal closer to your competition than a solid meal because liquids are emptied from your stomach faster. This is especially useful if you are nervous and tense.

If you compete at all-day events such as track meets, swimming meets, or tournaments, nutritious food choices may be a problem because you could be tempted by whatever is available at convenient concession stands. Consider the amount of time you have between your events, bring nutritious foods, and plan accordingly.

Suggested precompetition menus include the following:

1 hour or less before competition

  • fruit and vegetable juice such as orange, tomato, or V-8, and/or
  • fresh fruit such as apples, watermelon, peaches, grapes, or oranges and/or
  • 1 and a half cups of a commercial sport drink like Gatorade.

    2 to 3 hours before competition
  • fresh fruit, fruit and vegetable juices, and/or
  • breads; bagels; English muffins with limited amounts of butter, margarine, or cream cheese; or lowfat yogurt; and/or
  • 4 cups of a commercial sports drink like Gatorade.

    3 to 4 hours before competition
  • fresh fruit, fruit and vegetable juices, and
  • breads; bagels; baked potatoes; cereal with lowfat milk; lowfat yogurt; sandwiches with a small amount of peanut butter, lean meat, or lowfat cheese; and/or 7 and one-half cups of a commercial sports drink.

Does eating sugary foods before exercise improve performance?
Athletes sometimes consume simple carbohydrates such as sugars, honey, candy, or soft drinks right before exercise in hopes of getting "quick energy." Unfortunately, eating sugary foods won't provide it. Most of the energy for exercise comes from foods eaten several hours or even days prior to the start of the race or competition.

However, if you are an endurance athlete, new evidence suggests that eating some sugary foods (like energy bars, some types of candy bars, or sports drinks) 35 to 40 minutes before competition may benefit you by providing energy (glucose) to your exercising muscles when your other energy stores have dropped to low levels. Nevertheless, some athletes are sensitive to having their blood sugar levels go up and down quickly, and eating sugary foods right before their event could harm their performance. You need to experiment and find out what works best for you.

Does caffeine improve performance?
Initially, researchers thought that caffeine improved endurance performance by stimulating a greater use of fat for energy so that less of the stored energy in your muscles (glycogen) was burned. However, more recent caffeine studies don't support that theory. When caffeine improves endurance, it does so by acting as a stimulant.

Caffeine does not help everyone. Some people are extremely sensitive and have negative side effects including nausea, muscle tremors, and headaches. Too much caffeine can cause you to produce more urine and lose more water, especially in hot weather. You could become dehydrated and hurt your performance.

The International Olympic Committee has declared caffeine an illegal drug in international competition. Caffeine- containing tablets used prior to or during exercise should be used with caution due to their extremely high concentration and the possibility of overdosing.

What should I avoid for my precompetition meal?
The hot dogs, doughnuts, nachos, potato chips, and candy bars found at most concession stands are extremely high in fat and not digested quickly. These foods eaten as pre- event meals will likely be in your stomach much of the morning or afternoon. Avoid or limit eating these foods for your pre-event meal.

CLOSE