Abstract: A wearable monitoring device is provided to detect the physiological condition of a user and alert emergency services if needed. As provided herein, the monitoring device may include a band configured to be worn on a user's wrist; two or more operably connected PPG sensors arranged on the band, wherein at least two of the two or more PPG sensors are arranged such that the sensors contact opposite sides of the user's wrist when the device is being worn and wherein the at least two PPG sensors provide a higher signal to noise ratio as compared to a single PPG sensor; and a processor configured to receive and process readings from the at least two PPG sensors. Methods of using the monitoring device are also provided.