Extraction of Heart Beat Rhythm and Respiratory Rhythm in the Facial Temperature Fluctuations

Abstract

We attempted to investigate relationship among facial temperature of skin, heart beat rhythm and respiratory rhythm. Flames of facial thermal image were recorded every 50ms by IR-camera with a real time recorder and temperature per area of forehead was calculated by a personal computer with 4 transputers. ECG were recorded on a magnetic tape of data recorder and heart rate was computed by R-R interval of the ECG waveform. Experiments were performed in two ways. 1) subjects were sitting on a chair at rest while the temperature was measured. 2) Subjects had exercises in which they pulled rapidly and kept powerfully the back muscle dynamometer for 10s. Temperature fluctuation was analyzed in both kinds of experiment by a spectrum analysis of frequency. Peaks of the fluctuation were coincident with those of respiratory rhythm and of heart beat rhythm, respectively. At rest; 0.17Hz and 0.25Hz. During and after exercise, 0.15Hz and 0.45Hz. It is proved that heart beat rhythm and respiratory rhythm are included in the spectral pattern of the facial temperature.