Everytime i walk briskly on a treadmill, i have anal/rectal bleeding. i had colonoscopies and a fistula removed, this is still happening. why? thanks.

Consider hemorrhoids: I would suspect you have hemorrhoids and that vigorous activity is irritating the area. Take a stool softener, drink plenty of liquids, and if the bleeding continues it would be important to see a GI doctor and have a colonoscopy. Cancer, diverticulosis, and inflammatory bowel disease are other possibilities.

Hemorrhoids?: My first guess would be hemorrhoids but that is without knowing anything else. I strongly urge you to see your doctor for further evaluation.