I have a question. If you're a naturally lean guy like me with very low body fat, how much cardio should you do in a week that even though good for your heart rate will prevent you from burning muscle-if your goal is to bulk up? I don't think I don't think I need to run on an elliptical three days a week and even two days a week seems a lot for me. So far, I seem to be more inclined to try once a week. The thing however is that I've been working very hard on my abs and from what I hear, the secret to having and keeping good abs is cardio. At the same time, I don't want to lose my bulk. So would one day of good fat burn cardio on the elliptical be enough for me if my goal is to primarily bulk up rather than lose weight? My aim is to build a lot more muscle mass.