Great question. For this workout, I can go anaerobic during one section 1) the several drills at the end with the jump kicks and jump kicks out of squats ... I am anerobic only if I jump high, kick high and hard, squat deep and put everything into it. I need to take a grapevine break between drills because my heart rate is in the anaerobic zone and I need to get it down before I move to the next drill. For me, I would consider this three intervals (that is why I ranked this as one of the most challenging cardio workouts up there with MIC in a previuos post) but I am interested in Cathe's opinion too. I sometimes do this workout by modifying and toning down a notch or two and keeping my heart rate down in the aerobic training zone. That lo-impact thing at it's high-intensity best can also get my heart up there too.