I've been exercising on an exercise bike for the past 2 weeks 4 days a week. I've lost 5lbs and I've been eating better. I try to keep my heart rate between 130 - 140 range throughout my 30 minute exercise. Someone was telling me to burn fat you want to keep it between 120 - 128 and anything over 130bpm will start burning carbs for a cardio workout. Anyone have any info on this?