rct of effects of device-guided breathing on ambulatory bp

Conditions: Hypertension

Summary: our aim is to conduct a randomized controlled trial (rct) to test the efficacy of a guided breathing intervention on ambulatory blood pressure (abp), both systolic and diastolic bp. there are 3 groups: 1) intervention group instructed to use the resperate device that guides the breath into the 6 breaths/minute range daily for 8 weeks. 2) relaxation control condition (using a modified device to guide breathing at 13 breaths/minute rate); and 3) usual care (uc). after the initial 8 week trial, the main outcome, the intervention group will be randomly assigned to stop using the resperate device or to continue using it for 8 more weeks.

device-guided breathing is a behavioral intervention that guides the breathing into the 6 per minute range, inducing respiratory sinus arrythmia (rsa), which is the natural cycle of arrythmia that occurs through the influence of breathing on the flow of sympathetic and vagus impulses to the sinoatrial node of the heart. it has been shown in several small trials to have substantial effects on bp reduction, has no known side-effects, and may represent a cost-effective adjunctive treatment for hypertension. an important consideration is that, often, behavioral interventions are given for a brief amount of time, but are expected to have long-term effects. this does not hold true for medication; one would not give anti-hypertensive medication for eight weeks and expect an effect on bp several months later. the development of behavioral interventions needs to take into account methods to sustain long-term effects. our aim is to conduct a randomized controlled trial (rct) to test the efficacy of a guided breathing intervention on ambulatory bp (abp) in hypertensives drawn from primary care and specialty hypertension practices, using a sample size powered to detect effects at 8 weeks and 4-month follow-up. the design calls for two control groups: usual care (uc) and a relaxation control condition (using a device that gives the same type of feedback sounds as the guided breathing feedback device, but modified to pace the breathing at approximately 13 breaths per minute, a normal resting rate.) the intervention condition has participants use the resperate device that guides the breath into the 6 breaths/minute range. the initial intervention lasts eight weeks, following which participants are further randomized to either: 1) ending the intervention; of 2) continuing the intervention for the next 8 weeks. the main outcomes are the change at 8 weeks in systolic and diastolic bp (measured by ambulatory bp monitoring) during the waking hours. outcomes are measured at baseline, 8 weeks, and 16 weeks. the primary outcomes are bp results at 8 weeks, with a 3-group comparison of the intervention group, the relaxation control group and usual care.

Eligibility criteria:
inclusion criteria: * diagnosis of hypertension * treated with at least one antihypertensive drug * bp still not controlled (\>135/85 on ambulatory bp waking average) exclusion criteria: * diabetes * atrial fibrillation * pregnancy

Keywords: device-guided breathing hypertension behavioral intervention stress reduction heart rate variability (hrv) biofeedback