Methods: This study comprises a mixed population of military RC personnel, veterans, and civilian first responders. Participants used the BART mobile app on a personal smartphone with a Polar H7 heartrate monitor during an initial training session, a 6-week practice period, and a 46-week maintenance period; during app use, continuous HRV measures were acquired during rest, cognitive stress, resting recovery, and paced breathing training. HRV biofeedback was provided via a trending color-coded HRV chart to show movement between calm and stressful states, reflecting higher and lower parasympathetic activation. For the first six weeks, participants practiced the resilience training 3 times per week, then they were encouraged to practice frequently during the maintenance period. Psychological outcome measures were taken via in-app surveys at baseline and quarterly over twelve months.
Results: Of 350 enrolled participants, 207 were included in our analyses. Protocol adherence analyses found a sharp drop off rate over the six-week practice period. A total of 3136 training episodes were initiated with over 600 sessions conducted during the first week, after which training compliance fell by almost a third and after then by about one-half over subsequent weeks. HRV decreased significantly from rest to cognitive stress (p<.002), then rebounded during the post-stress recovery. During resilience training, HRV increased significantly (p<.0001) reflecting strong parasympathetic activation accompanying the paced breathing practice exercise.
Discussion: Results indicate that the BART app provides useful paced breathing resilience training with biofeedback and acquires quality data for studying changes in mind/body activity states. Self-administered resilience training delivered via smartphone will permit military personnel to train anytime, anywhere with less cost and more convenience than group training classes, which is especially beneficial for RC personnel.