Evaluation of Drowsiness During Driving using Electrocardiogram - A Driving Simulation Study

Drowsiness during driving causes traffic accidents frequently. It is therefore desirable to detect the drowsiness. Drowsiness occurs when the parasympathetic nerve activity becomes dominant. Related researches show that high frequency (HF) component of heart rate variability (HRV) on an electrocardiogram (ECG) has certain correlation with drowsiness by reflecting the parasympathetic nerve activity. In this study, the driving experiments were conducted with a simulator, where the ECG was recorded, and the heartbeat intervals were calculated. The power spectrum of HRV was analyzed by Fast Fourier Transform (FFT), and the temporal change of HF band was analyzed. In addition, low frequency (LF) to HF ratio (LF/HF), which is considered an indicator for the sympathetic nervous system, was also investigated. The results show that in the data of six out of ten experiments, the correlation among subjective drowsiness, HF is high. Some experimental results also show positive correlation between subjective drowsiness and LF/HF.