Researchers led by Ida T. Fonkoue at Emory University and the Atlanta Veterans Affairs Medical Center report that eight weeks of daily device-guided slow breathing reduced sympathetic nerve reactivity to acute mental stress in veterans with post-traumatic stress disorder (PTSD), according to a study published in the American Journal of Physiology–Regulatory, Integrative and Comparative Physiology.
In a randomized, double-blind trial, 25 military veterans with PTSD and mildly elevated blood pressure were assigned to 15 minutes per day of either an active guided-breathing device or a placebo device for eight weeks. The active device used abdominal sensors and audio cues to slow breathing to about five to six breaths per minute. The placebo device provided similar music but kept breathing at roughly 14 breaths per minute.
Investigators measured resting heart rate, resting blood pressure, baroreflex function and sympathetic nerve activity before and after the intervention. Sympathetic nerve signals were recorded directly with microneurography, inserting a tungsten microelectrode into a leg nerve to count impulses in real time.
The trial found no change in resting blood pressure, resting heart rate, resting nerve activity, baroreflex function or PTSD symptom scores in either group. However, during an acute mental-stress task (three minutes of rapid mental arithmetic with timed pressure), the active breathing group showed a smaller increase in muscle sympathetic nerve activity than they had at baseline. The placebo group’s nerve responses to the task remained unchanged. Blood pressure spikes during the stress test were similar in both groups.
The authors note important limitations: the sample was small and predominantly African American male veterans; recordings measured only nerve traffic to skeletal muscle, not to organs such as heart or kidney; and a brief medication abstinence before testing might not have removed drug effects. They call for larger trials to test whether reduced sympathetic reactivity translates into lower cardiovascular risk or changes in inflammation and heart-rate variability over time.
The study, “Eight weeks of device-guided slow breathing decreases sympathetic nervous reactivity to stress in posttraumatic stress disorder,” lists Ida T. Fonkoue, Yingtian Hu, Toure Jones, Monica Vemulapalli, Justin D. Sprick, Barbara Rothbaum, and Jeanie Park as authors.
Photo credit: www.psypost.org
Tags: PTSD, device-guided breathing, muscle sympathetic nerve activity, biofeedback, cardiovascular risk
Topics: Biofeedback & neurofeedback, Wearable neurotech, Stress, focus & mental clarity