What Exactly is a Cardio Workout?

I had an interesting discussion yesterday with a certified professional training about what is a cardio workout and do you really need cardiovascular training to get in great shape.  Most fitness buffs and weekend warriors consider it a fact that you need cardio exercises to get in shape, lose body fat, and develop lung capacity.  You may be surprised to know that some of the leanest and meanest people never do any type of traditional cardiovascular training. More...