How many beats per minute should the heart beat?

Depends. Our heart works to provide adequate blood flow, usually described in liters/min.To reach this value the heart ejects a certain volume with each beat, known as the stroke volume (sv described as ml/beat). This is multiplied by the heart rate (beats/minute) to yield a volume per minute. The blood flow needed depends on what you are doing, sleeping requires alot less than exercise.The rate will vary.