A Heart Rate Monitor is the only effective way to track and record your heart rate over the course of an entire workout. The purpose of measuring and recording your heart rate is for you to have instant feedback about the work level of your heart during exercise. A hear rate monitor will not only help you over stressing your body but will allow you to maximize the efficiency of your training and avoid injury. Injuries are less likely to occur when you are not over-taxing your body! Using a heart monitor also allows you to meet your cardiovascular goals while working out.