Truth is seeing how many total calories you can burn total for the session. More total calories each time, the more fat is burned....period. The zone may be higher than the suggested zone for some, so this strategy is for definitely the strong at heart. We suggest a heart rate monitor be used instead of relying on machine monitors when doing cardio in a gym. Also wear your monitor while weight training in the gym. The watch should have a calorie counting/storage mechanism for best results. A simple goal may be to get between 10-15 calories per minute throughout the workout. 30 minute workout equals 300 calories. If this is easy, move to the next level is 15-20 cal/min. If not quite able to do10 calories a minute, start with 5-10 and work up. Meet or beat every workout from this point forward by 1 or more calories burned every time and I guarantee fat loss.