Analysis of HR, HRV, and data reduction
The HR and HRV of each participant were obtained based on the time series of peak‐to‐peak intervals immediately extracted from the BVP data. The HR and HRV are computed by taking the peak‐to‐peak distances between beats. Before analyses, we visually checked the normal‐to‐normal intervals (NN intervals), movement artifacts, and unusual heartbeats for artifact rejection. Afterward, we used the NeXus‐10 device‐supplied software BioTraceThe HRV time domain was represented in the present study by the SDNN (ms) and the RMSSD (ms). We calculated the frequency‐domain parameters using the FFT algorithm (FFT window length = 512, Hanning window, 1024 points). As mentioned above, the primary HRV frequency‐domain indices are the LF (ms