Pulse arrival time measurement with coffee provocation.

This study investigated the effect of coffee intake in pulse arrival time (PAT) and pulse wave velocity (PWV) measured with electrocardiogram (ECG) from arms and photoplethysmogram (PPG) from fingertip. In addition, correlation of PWV with blood pressure (BP) is analyzed. 30 healthy participants were recruited to two measurement sessions, one arranged before and another one after the coffee intake. During each session, ECG and PPG were measured continuously for six minutes and PAT values calculated from ECG R-peak to the maximum of the first derivative of the PPG pulse. In addition, blood pressure was measured twice during each session with cuff based method. Coffee intake had statistically significant influence on both systolic and diastolic blood pressure, but not on PAT or PWV. Correlation between systolic blood pressure and PWV was 0.44. Individual calibration, additional derivatives of ECG and PPG such as heart rate, pulse pressure, or waveform characteristics could improve the correlation.