I have had a lot of trouble with leg and stomach cramps when I work out. The leg cramps were more tolerable, but the stomach cramps are unbearable. When the sharp pain in my side comes on it is nearly impossible to keep running, and once they start they do not go away for the entire work out. I think the main reason for the problems is that I sweat a lot. A couple years ago I found a product called Calucet which is basically a combination of Calcium and Vitamin D. I started taking 2 pills in the morning and that totally fixed my cramps. Lately the Calucet is talking care of everything but the stomach cramps. I have tried changing how long between the last time I ate and that has had very little impact. During almost every work out (mostly jogging) I can run for 5 to 10 minutes and then the pain sets in and makes it impossible to do anything but walk.