Do you know where your heart is? Sure, it could be inside your body, but do you REALLY know? When's the last time you checked? When's the last time you saw it? When's the last time you had visual proof? It could be there, but it could also NOT be there. Keep your heart monitored; it's the only way to be sure it's there.
About Oregon Scientific Heart Rate Monitors
Considering Oregon has the highest percentage of runaway hearts, it's only natural that they would design a heart rate monitor.