Fig. 1

Detailed description of physical factors in pulse waves. a Sum-30p-PPI: sum of the pulse wave areas of the region from the 30 % point of PPI to PPI. b Sum-30p: sum of the pulse wave areas of the region of the pulse waves with amplitudes higher than 30 % of PPI. c Sum-1.12v-PPI: sum of the pulse wave areas of the region from 1.12 V point to PPI (1.12v means detection voltage of the pulse in the KIOM pulse wave detector device). d Sum-1.12v: sum of the pulse wave areas of the region with pulse amplitudes higher than 1.12v. e PSD_w1: Power spectral density (PSD) at the first harmonic frequency from the acquired pulse wave. f Asys_HR75: Area of systolic period after normalization with HR75 (heart rate of 75 bpm) for comparison among various heart rates