Actually running is probably the worst exercise that someone can do. It's bad on the whole body, stressing and pounding the body creating more damage than practically any other exercise. There is not one good results that has any good purpose from running that cannot be gained from safer less stressful exercise. With all the injuries I see caused by running it's ridiculous that professional therapist and doctors keep recommending it (even for knee injuries). But of course people know the dangers of smoking and continue to do it.