All human beings have some sort of reference point for measuring “Time” or your inner clock. For most people, their frame of reference is their heart beat. Think about it. Even in the womb, we are exposed to a sense of timing – a pulse which is steady and even. To illustrate this point look at the facts. A person’s heart rate gradually slows as they age. Teenagers, for example, have a faster heart rate than someone in their fifties. Therefore, when it comes to music lessons, teenagers have a bit more difficulty playing steadily at a BPM like 50 or 60. Whereas, someone in their fifties would find it a little easier to play steadily at those slower tempos.