What's your usual? Maybe a five-mile run in the morning, or a bike ride after work? Perhaps you get some cardio in by stalking the gym during lunch hour looking for a free elliptical.
We all have our routines. And those of us who like to mix in some exercise regularly often develop a set regimen, or at least a preferred context for our exertions. With that in mind I'd like to ask a rhetorical question: When you return from your morning or evening constitutional, when you towel off after your "usual," are you the same person you were when you began? If the answer to that question is "Yes," then let me humbly suggest there is much more to be gained from your endeavors than mere exercise.