Not Cathe, but here's what I do, and it works well for me. I lift heavy 3 days per week, and do about 20 minutes of interval cardio after lifting on those days. I do one or two days of longer, moderate intensity cardio. This can be done numerous ways - bootcamp-type workouts, circuits, kettlebells, running, elliptical training, spinning... Just keep your heart rate in the 80-90% range for the duration of your workout. I don't do long, low intensity cardio - for me it didn't produce results and I found it boring and frustrating. The only exception is during the summer when I go for a long run (6-13 miles).