Comparison of heart rate variability measures for mental stress detection

Mental stress is one of the well known major risk factors for many diseases such as hypertension, coronary artery disease, heart attack, etc. Conventionally, detecting mental stress in an individual is performed by interviews and/or questionnaires. In this study, we have investigated various heart rate variability (HRV) measures for detecting mental stress by using ultra short term HRV analysis. A number of HRV measures were investigated, e.g, Mean of heart rates (mHR), Mean of RR intervals (mRR), Power spectra in Very Low (VLF), Low (LF), and High (HF) frequency ranges, Symphatovagal balance index (SVI), etc. Experiments involved 60 segments of RR interval time series signals during mental stress state and normal state. Results revealed that the following HRV measures: mRR, mHR, normalized LF, difference between normalized LF and normalized HF, and SVI were effective measures for mental stress state and normal state classification.