Abstract: In embodiments of wearable device heart monitor systems, a wearable device has electrical contacts integrated in a housing base of the wearable device as electrodes designed to contact skin of a user while wearing the wearable device. A housing bezel of the wearable device designed as an additional point of contact on the wearable device. The wearable device includes an electromyography (EMG) system to receive electrical signals from at least two of the electrodes and detect muscular movement of the user. Further, the wearable device includes an electrocardiogram (ECG) system to receive and combine the electrical signals from the electrodes when the user touch contacts the housing bezel while wearing the wearable device to complete an ECG loop between the electrodes and the housing bezel for a heart rate reading of the user.