Stomach cramps are one of the most unpleasant, uncomfortable problems associated with running. During a run, cramps or stitches can seriously hamper your performance. If the cramping continues hours after running, however, it can lead to more serious problems. Dehydration does not cause cramping, but cramps can easily lead to dehydration, either through diarrhea or because stomach pain prevents you from drinking enough. If you regularly suffer severe cramping after running, consult your doctor.