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Seven separate
studies 1-7 (see Mechanism of Action) have examined the decrease in office
blood pressure for subjects who used the device for 15 minutes/day for
8 weeks, compared to “control” interventions
(listening to relaxing music 1 or home BP monitoring 4-5 or both 2 ).
Four studies were double-blind and randomized 1,2,5,8 , one was controlled
and randomized 4 , and two were open-label experiences 3,6. A total of 286 individuals participated in the seven studies: 55% were men; 78% were drug-treated, with average age of 58 years; Body Mass Index of 28 kg/m2; and initial office BP of 150/90 mmHg (9% pre-hypertensive; 25% Stage 2). The decrease in office BP after 8 weeks of device-guided breathing among those with uncontrolled hypertension was 14/8 mmHg, compared to control treatment of 9/4 mmHg (p = 0.008 and p = 0.002, respectively for systolic and diastolic BPs). The difference was independent of gender and medication status. Control of BP (< 140/90 mmHg) was seen more commonly in the group that used the device: 26% vs. 4% of those with initial Stage 2 hypertension (> 160/100 mmHg, < 0.005); and 48% vs. 34% for those with initial Stage 1 hypertension (140-159/90-99 mmHg, p < 0.05). The drop in office BP was directly related to the duration of slow breathing during the 8 weeks of treatment; those who used the device to achieve slow breathing more than 15 minutes/day had the greatest lowering of office BPs. It usually takes 3-5 weeks to achieve a sustained reduction in home BP. Larger decreases in office BPs were seen in older individuals and those with higher baseline BPs, whether taking antihypertensive medication or not. Verification of BP lowering has also been seen with home BP measurements (for up to 6 months of use7) and ambulatory BP monitoring3. |
