What kind of working out do you do? How old are you? You don't want to work out so much you cause damage. You don't want to run before bed because it stimulates the system and makes it hard to get good sleep. Running eventually will damage you, so you have to decide, are you an athlete and love your exercise enough to possibly stress your body, or are you just someone who exercises for health? A lot goes into exercising, as you can see, and it differs by the person.