Within-group comparisons indicated statistically significant differences between baseline and post-AP pressure HR ( -2.8 bpm ; 95 % confidence interval : -4.6 , -1.1 ) and between baseline and post-AP pressure systolic BP ( -2.4 mmHg ; 95 % confidence interval : -3.7 , -1.0 ) in the AP group , and between baseline and postplacebo systolic BP ( -2.6 mmHg ; 95 % confidence interval : -4.2 , -1.0 ) in the placebo group .