These pulse or heart rate monitors for the wrist allow precise, stress-oriented training for cyclists, runners and other endurance athletes. Most of the models measure the heart rate with a separate chest strap via two skin electrodes and send the current load data to the watch on the wrist. A second system measures the pulse values directly on the wrist. It is essential for effective training with heart rate measurement to determine your own maximum pulse, and the correct pulse ranges for different training goals, and to be able to decide on an optimal range for the training unit on the device. The regular sports-watch functions such as lap times, countdown and much more come as standard on almost every model.