*3.1. Subjects*

We recruited 18 subjects (8 females and 10 males, aged 24.6 ± 4.6) from Pohang University of Science and Technology (POSTECH), South Korea, via open recruiting. The study subjects were selected based on the following criteria: (1) they had no cardiovascular disease or mental problems and (2) they had not undertaken intense exercise before the day of the test and (3) they had not had caffeinated beverages on the day of the test. This study was approved by the POSTECH Ethics Committee (PIRB-2019-E001).

The experiments were conducted in parallel with the recruiting process. Although most experiments proceeded normally, unexpected technical problems (namely a subject's carelessness and an unexpected Windows OS update) occurred during two experiments, meaning that these two subjects' data were not captured correctly. Thus, we only considered the datasets collected from the remaining 16 subjects.
