What to Eat Before Exercising in the Heat

Regular exercise promotes overall health and increases strength and stamina. However, even the most experienced exercisers can fall victim to heat-related illnesses. Prolonged exposure to heat during exercise may result in heat cramps, fainting, exercise exhaustion or heatstroke. Symptoms of heat illness include dehydration, weakness, dizziness, excess sweating, headache and clammy skin. Extreme cases can result in organ failure or death. Taking steps to ensure proper nutrition and hydration can prevent low energy and dehydration.

Nutrition Considerations

• Proper nutrition is essential for peak performance and physical comfort during exercise. When you exercise in high temperature conditions, your carbohydrate needs rise. Consuming carbohydrate- and fluid-rich foods such as fruits prior to exercise in high temperatures can provide both energy and hydration. Along with drinking an adequate amount of water, eating a banana 10 minutes prior to exercise can help maintain athletic performance and decrease exercise-related inflammation.

Sodium and Hydration

• Increased sweating due to prolonged exercise in high temperatures can cause excess sodium and fluid loss. Dehydration due to water loss of 2 percent to 3 percent of body mass increases perceived exercise difficulty and decreases performance. Consuming foods with a small amount of salt, such as pretzels or a sports drink, prior to exercise can encourage you to drink fluids. In warm, humid environments, exercisers should drink 7 to 10 ounces of water 20 minutes before exercise and at least 6 ounces of fluid every 20 minutes during exercise. Water is the best fluid to prevent dehydration unless you exercise for more than 60 minutes, the American Council on Exercise says. More than an hour of exercise in hot environments may require a sports drink to provide sodium and carbohydrates.
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Diet Effects on Hydration

• Foods and fluids consumed before and during exercise should not contain caffeine or alcohol. Just as caffeine and alcohol can, a high-protein diet can increase water loss through increased urine output. In addition, diets high in fiber -- 20 to 30 grams per day -- can slightly increase water needs. Avoid eating high-protein or high-fiber food prior to exercise in high temperatures.

Long-Term Diet Choices

• Replacing carbohydrate stores post-exercise by ensuring adequate carbohydrate consumption will aid in exercise performance during the next workout in hot conditions. A high-carbohydrate breakfast such as whole-grain cereal with low-fat milk and fruit will raise blood sugar and provide energy for exercise. Fruit juice can also provide quick energy before a workout. To aid muscle recovery and replenish carbohydrate stores prior to the next exercise session, eat a meal containing both protein and carbohydrates within two hours of the workout, such as peanut butter on toast or beans and rice.