Check out this article I wrote back in March for LoveToKnow.com.
When I first began my training (around 35 years ago) I had two primary objectives: get stronger and gain muscle size. Through hard work and dedication I accomplished those goals within three years. However, as fit as I was or so assumed, I always struggled with high intensity cardio activities. A lack of training one of the most important muscles in our bodies can diminish your performance, limit your potential and, in some cases, shorten your life span.