It is critical that the feed move through the stomach and small intestine before exercise. It takes 1-2 hours for the ingesta to move through the upper part of the digestive system. The reason for the wait is that blood moves out of the digestive tract and to the muscles during exercise. If the ingesta is in the upper part of the tract when the exercise-induced reduction of blood occurs, fermentation of carbohydrates occurs and creates gas, which causes gas colic.
