Cardio is an extremely versatile form of exercise. Sure, it can burn calories and keep you thin, but it canals help build lean muscle and trade fat for definition. This workout from trainer Joanna Soh is all about using cardiovascular exercise to target belly fat and shed some serious poundage. One of my favorite aspects of this workout is how it can be altered to fit beginners as well as more advanced fitness gurus. Try it out and be prepared to sweat!