Increases in heart rate can be caused by numerous artifacts, but the heart rate monitors that use the Snap-On Polar Module  with hand grips, such as the Go Wireless Heart Rate and the Hand Grip Heart Rate Monitor, can pick up changes in the electrical activity of the skeletal muscles of the arms and shoulders, especially if the subject is pumping their arms during running or moving their arms while siting. These muscle movements cause artifacts in the form of extra pulses that are interpreted as extra heart beats by the module and software applications. Additionally, moving the hands or fingers over the grips can cause noise as well. The resulting heart rate will appear to suddenly spike or appear to be artificially high.

To avoid these artifacts, the subject should try to keep the hand grips level and avoid pumping the arms. When running in place, the subject should hold the arms and hand grips steady and only move the legs. Exercise Heart Rate Strap should be used if the customer wants to investigate heart rate during vigorous activity.