Comparison of inter-night and within-night changes
To be able to estimate the effect of sleep interventions, we analyzed the within-night-changes while comparing sleep stages of baseline nights using Friedman-Test and calculated effect sizes for this too. There were several significant differences in post-hoc pairwise comparisons with effect sizes up to r = 1.659 (N2-W) in HR, up to r = 0.67 (N3-W) in SDNN, up to r = 0.42 (W-N1) in pNN50, up to r = 0.67 (N1-N3) in LF and up to r = 0.628 (REM-N3) in HF.Our data are suggesting that within night changes have thus a strong effect on HRV-parameters.