As many people are preparing to run the London Marathon on 26 April, one gastroenterologist has shared the reason a lot of marathon runners will often need to run to the nearest toilet at mile 18 of the race. Whether you're an experienced runner or someone who've just started out, chances are you might have experienced something called 'runner's trot'. This is the moment during or after a run when you get a urge to rush to the bathroom for a sudden bowel movement. While it may appear odd if you