2.6. Statistical Analysis
All the subjects’ demographic data as well as their HRV parameters were described using arithmetic means, standard deviations (SDs), and standard errors of the mean (SEM). The chi-squared test was used to test for gender differences between groups, and results were expressed in percentages. In addition, group differences were evaluated for age, body mass index (BMI) and HR using the two-sample In the present study, HRV analysis was executed using the restricted weak stationarity (RWS) test proposed by Porta and colleagues (2004), which assesses stationarity (i.e., the steadiness of the mean and variance, respectively) over M patterns [To assess the effect of PAP and SHAM-PAP interventions on the ANS, each time-domain parameter of HRV (SDNN, RMSSD, NN50, and pNN50, respectively) and the frequency-domain index of HRV (HF band) taken into account for this study were entered in a mixed analysis of variance (ANOVA) with INTERVENTION GROUP as the between-subject factor (two levels: PAP and SHAM-PAP) and TIME as a within-subject factor (two levels: pre-intervention and post-intervention). Post hoc pairwise analysis was conducted with Bonferroni adjustment for multiple comparisons. The threshold for statistical significance was set to 