Hi Jerry! For cardio workouts, the harder/heavier you breathe the more intense the workout. Regardless of the type of cardio it is, gasping for air is working too hard and whistling dixie is too easy...LOL!
Try to find a point between there and that will be moderate intensity. While at that point in the workout, push yourself to work harder on and off in between the workout and you will be considered moderate to high in intensity. Push yourself just a wee bit more and you will be more high then moderate in intensity. Push yourself CONSTANTLY throughout the workout and you will be working at more of an interval format which is considered very high intensity.
Gosh, I hope you followed all that....what was in that eggnog, just kidding!