Uma Thurman used to smoke so heavily that she couldnt do any exercise.The svelte Kill Bill star has said her cigarette addiction meant she was never physically fit enough for her leading roles. Uma told Britains Observer Woman magazine: "I used to smoke so much that I got out of breath if I did any exercise. I was never rippling and toned like a lot of my colleagues."That makes you incredibly depressed and full of self-loathing, so thank goodness Ive unhooked myself from the slavery of nicotine."The Pulp Fiction star finally decided to quit smoking to get in shape for her physically demanding role in the kung-fu Kill Bill films.