The technology described in this document can be embodied in a method that includes obtaining, using a first sensor disposed in a device, a first data set representing time-varying information on at least one pulse pressure wave within vasculature at the wrist of a subject. The method also includes obtaining, using a second sensor disposed in the device, a second data set representing time-varying information about chest vibrations of the subject, and identifying first and second points in the first and second data sets, respectively. The first point represents an arrival time of the pulse pressure wave at the wrist. The second point represents a chest vibration corresponding to an earlier time at which the pulse pressure wave originates at the heart of the subject. Pulse transit time (PTT) is then computed as a difference between the first and second points.
