Eight Weeks of Device Guided Slow Breathing Decreases Sympathetic Nervous Reactivity to Stress in Post-Traumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is characterized by increased risk for developing hypertension and cardiovascular disease. We recently showed that device-guided slow breathing (DGB) acutely lowers blood pressure (BP) and muscle sympathetic activity (MSNA) and improves baroreflex sensitivity (BRS) in PTSD. The aim of this study was to assess the long-term benefits of DGB on autonomic function at rest and during stress. We hypothesized that long-term DGB improves arterial BRS, lower BP and MSNA in PTSD. Twenty-five Veterans with PTSD were studied and randomized to either 8 weeks of daily DGB (n=12) or 8 weeks of Sham device (n=13). BP, heart rate (HR) and MSNA were measured at rest and during mental math. Arterial BRS was assessed using the modified Oxford technique. Resting MSNA, BP and heart rate (HR) remained comparable before and after 8 weeks in both groups (DGB and Sham). Likewise, the change in sympathetic and cardiovagal BRS was not different between the groups. Interestingly, DGB significantly decreased MSNA reactivity to mental math when expressed as burst frequency (P= 0.012) or burst incidence (P= 0.008) compared to sham, suggesting a sustained effect of DGB on sympathetic reactivity to stress in PTSD. Contrary to our hypothesis, long-term DGB did not lower systolic BP, diastolic BP or HR responses to stress compared to sham. Likewise, pulse pressure reactivity after 8 weeks (P= 0.121) was also comparable. In summary, these data suggest that long-term use of DGB may lead to a sustained dampening of sympathetic reactivity to mental stress in PTSD.

Keywords: PTSD; autonomic function; mental stress; slow breathing.

PMID: 32847397 DOI: 10.1152/ajpregu.00079.2020