부산대학교 도서관

This innovation is related to measuring the heart rate under unawareness of subject to extract the true nature heart rate variability. The heart rate variability (HRV) is an important index that could be used for long term monitor of cardiac function. The low variability of heart rate indicates that the cardiac rhythm could not be regulated by autonomic nerve system. This concept of monitoring vital under unawareness of subject has been innovated and devised into a portable apparatus that was monitoring photo-plethysmo-graphy (PPG) through an ear plug appliance. The system was used in assessing the psychophysical effect of heart beat monitoring over four circumstances. These were the situation of monitoring the ECG without listening to music, assessing the PPG without listening to music, listening to music with monitoring the ECG, and listening to music with the assessment of PPG. Four types of HRV parameters were analyzed among named four circumstances using Student's T-TEST. These were to examine the impact of heart beat monitoring methods on users. While examining the HRV frequency spectrum against each testing situation, the parasympathetic tone was found activated much earlier using PPG to assessing heart beat than the using ECG. This result demonstrated that the subjects' heat rate and their natural heart rate variability could be monitored unconsciously using PPG while listening to music.