A system that continuously monitors cardiovascular health using an electrocardiography (ECG) source synchronized to an optical (PPG) source, without requiring invasive techniques or ongoing, large-scale external scanning procedures. The system includes an ECG signal source with electrodes contacting the skin, which generates a first set of information, and a watch-like device, worn on a limb such as an arm or a wrist, having a reflectance-based PPG signal source that generates a second set of information. Together with a processing module, housed within the watch-like device and configured to receive and process the first and second sets of information, from which the time differential of the heart beat pulmonary pressure wave can be calculated, continuous data related to cardiovascular health markers such as arterial stiffness can be determined. Automated heart rate calibration of the reflectance-based PPG sensor can also be achieved.
