Carbohydrates are a major fuel source used during running and should be a major component of your diet whether you are training for a long-distance event or just running to keep in shape. The amount and type of carbohydrates you consume are important, as is the timing of your intake. Adequate intake of the appropriate carbohydrates before, during and after a run optimizes your performance and aids in recovery.
Simple Versus Complex Carbohydrates
Carbohydrates are rated according to a glycemic index, a measure of how they affect blood sugar levels. Simple carbohydrates have a high glycemic index as they are easily digested and quickly released into the bloodstream. They are found in foods made from refined flour such as white bread and pasta, as well as those with high sugar contents such as cake and candy bars. Complex carbohydrates have a lower glycemic index; they require a longer time to be digested and are released more gradually into the bloodstream. Whole grain breads and pastas, oatmeal and muesli are good sources of complex carbohydrates.
Carbohydrate Metabolism During Running
The body gets its carbohydrate fuel in the form of blood glucose or muscle glycogen--a storage form of glucose. Reliance on both energy sources increases as the tempo of the run increases, and according to A. Foskett in the January 2008 issue of the "Medicine and Science in Sports and Exercise," provides up to 70 percent of the total energy expended during high-intensity events. Low blood glucose or hypoglycemia and depleted muscle glycogen stores lead to fatigue and reduce performance during running. To avoid this, many competitive runners practice carbohydrate loading--consuming a high carbohydrate diet in the days leading up to their event.
Carbohydrates Before Your Run
According to Dr. Robert Wildman in the February 2010 issue of the "Strength and Conditioning Journal," consume 200 to 350 grams of carbohydrate three to four hours before running in order to maximize muscle glycogen stores. This amount can be spread over two meals and should come from complex carbohydrates. Try not to eat a heavy meal or one high in fiber in the hour before your run, and choose dietary carbohydrates that are easily tolerated to prevent stomach discomfort during the workout. A good example of a pre-run meal is a cup of low fat yogurt and a slice of whole wheat toast, but experiment to see what works best for you.
Carbohydrates During Your Run
Consume carbohydrates during your workout to maintain blood glucose levels and provide the working muscles with a source of fuel. This is especially important for runs lasting longer than an hour, where muscle glycogen stores begin to wane. Easily tolerated foods such as sports drinks or carbohydrate gels are good to consume during your run as they provide an immediate source of carbohydrates and also help replace fluids lost through sweating.
Carbohydrates After Your Run
Consume carbohydrates after exercise to replace depleted glycogen stores and to assist protein synthesis, which helps rebuild muscles broken down during long and high intensity runs. The timing of this ingestion is crucial: according to Dr. John Ivy in the June 1998 issue of the "International Journal of Sports Medicine," endurance athletes should consume at least 0.75 grams of carbohydrate per pound of body weight within 30 minutes of the end of the run. Your postworkout meal should also include a small amount of protein, which helps to improve muscle glycogen resynthesis. Good examples of postrun meals include fruit smoothies and chocolate milk.
References
- "Journal of Applied Physiology"; Higher dietary carbohydrate content during intensified running training results in better maintenance of performance and mood state. Achten J, Halson SL, Moseley L, Rayson MP, Casey A, Jeukendrup AE.; April 2004.
- "Medicine and Science in Sports and Exercise"; Carbohydrate availability and muscle energy metabolism during intermittent running; Foskett A, Williams C, Boobis L, Tsintzas K.; January, 2008
- "International Journal of Sports Medicine"; Glycogen resynthesis after exercise: effect of carbohydrate intake; John L Ivy, PhD; June, 1998
- "Strength and Conditioning Journal"; Carbohydrates, Physical Training and Sport Performance
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