HRV was measured through R–R interval analysis using a heart rate monitor42 (link) positioned onto the participants’ chest (V800, Polar Electro Oy, Kempele, Finland) during the entire duration of the protocol, except during PBC sessions. To avoid HR fluctuations, the test was performed in a quiet and dimmed-light room, and participants remained still in a sitting position. Time series of R–R intervals were extracted using the Polar Flow software and analyzed with Kubios software (v. 3.3.1, 2019, Finland). The HRV analysis concentrated on data collected during the Stroop tasks performed before and after the PBC or control session.
R–R intervals during 128 s (to fit with the duration of the Stroop task) were analyzed using time-domain indices (mean HR and root mean square of the successive differences, RMSSD), frequency-domain indices (low-frequency band, LFnu; high-frequency band, HFnu, and LF/HF ratio) and nonlinear indices (standard deviations perpendicular to, SD1 in a Poincaré plot analysis), which were associated to parasympathetic tone.
R–R intervals during 128 s (to fit with the duration of the Stroop task) were analyzed using time-domain indices (mean HR and root mean square of the successive differences, RMSSD), frequency-domain indices (low-frequency band, LFnu; high-frequency band, HFnu, and LF/HF ratio) and nonlinear indices (standard deviations perpendicular to, SD1 in a Poincaré plot analysis), which were associated to parasympathetic tone.
Free full text: Click here
