Athletes tend to do a good job of training their muscles, heart and lungs. But some of them (particularly endurance athletes and those in running sports) commonly fail to train their gut.

As one marathoner reported, "I was so afraid of getting diarrhea during long training runs that I did not eat or drink anything beforehand. I really struggled after 14 miles. ..."

A high school soccer player admitted, "I'm so afraid I'll throw up if I run with food in my stomach." He ate only a light lunch at 11:00 and then practiced on fumes at 3:30. No wonder he had a disappointing season.