almost every time i run or do the eliptical i feel like i have to poop, the strange thing is, i never really have to go its just a sensation, and its not a comforatable urge either, it first feels like lower abdominal period cramps or like im about to have diarrhea, then if i continue doing whatever im doing it quickly waves upward into nausea and i get really sweaty and the color drains from my face. I actually fainted on the way into the bathroom to vomit the first time i had this sensation, this was last january. now if i get those diarrhea cramps i stop what im doing because i dont want that to happen again. But after the cramps pass i feel weak, its bizzare. Im 5'7" 135lbs, i eat a normal diet, and i keep very well hydrated so i dont believe its due to dehydration or malnutrition. i take 20 mg Paxil daily for anxiety, and i have mild asthma that is controlled with flovent and prn albueterol. im otherwise very healthy! im 22 years old. I'm wondering if this is a vagus nerve response from bowel stimulation from excersise? It doesnt happen every time i work out, but its been happening enough for me to wonder about it because it cuts my workouts short. i dont get the sensation when i swim so i prefer to do that most of the time. any thoughts/suggestions would be great!