Hi, I just started to consistently do cardio workouts. I ride the bike 30 minutes a day. Right now, I ride with a heart-rate of 160 beats-per-minute, my 80% max heart rate. The machine says that 65% max heart rate, or 130 beats-per-minute, is the fat-burn zone whereas the 80% max heart rate is the cardio zone. Can you burn as much, or more fat, given the same amount of workout time, @ 80% vs. 65%? Thanks in advance for answers.