What is disclosed is a system and method for determining arterial pulse transit time (PTT) for a subject. In one embodiment, time-series signals are received for each of a proximal and distal arterial site of a subjects body which represent blood volume changes in the microvascular tissue at each site. A proximal and distal analytic signal is obtained which has a first component being a waveform of the respective time-series signal and a second component being a transform of the respective waveform. A phase function is determined for the first and second components of each analytic signal. The phase function obtained for the proximal waveform is then subtracted from the phase function obtained for the distal waveform to get a phase difference. The phase difference is analyzed with the subjects heart rate to determine an arterial pulse wave transit time between the two proximal and distal sites.
