Since I began running several years ago, I have been plagued by running-induced bowel problems. Almost like clockwork, I have to take a bathroom break at the 30-40 minute mark--and then every 30-40 minutes after that. Sometimes I have diarrhea, other times just loose stool. I finally decided to schedule an appointment with a doctor, and she immediately diagnosed me with irritable bowel syndrome and prescribed Bentyl. I'm worried about taking this medicine (possible side effects include impaired ability to sweat and thermoregulation problems). I'm also suspicious that she jumped to the IBS diagnosis. Has anybody had similar experiences (i.e. bowel problems ONLY while running)? How about taking Bentyl?
Note: I tried cutting out lactose for a few days with no luck.