Abstract
In order to grasp the mental stress level, heart rate variability (HRV) is one of the objective criteria. Generally, HRV is calculated from the heart rate or the pulse using electrocardiogram (ECG) or photoplethysmogram (PPG), which requires special measurement devices and technical knowledge. However, for the purpose of measuring the mental stress level in everyday life, a convenient device, which can be used at any time, is necessary. Therefore, we developed an application to gauge the mental stress level by using a readily available device, the smartphone, to calculate HRV in accordance with the human-centered design (HCD) process and conducted the evaluation among both young and elderly users.
